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GET IT NOWCasseroles are some of my favorite healthy dinners because you only need to make one dish—no need for a separate main and side. And even though my chicken zucchini casserole has some pre-cooking steps (as casseroles often do), I still love the simplicity of this one-recipe meal. And the perfect excuse to use more zucchini. And the cheesy gruyere sauce that totally feels like comfort food. Make it with me and make the most of zucchini season!
Why You Need My Chicken Zucchini Casserole
- Luscious gruyere cheese sauce – The sauce is what sets this one apart from your run-of-the-mill chicken casserole. You’ll love the rich, cheesy, and bold flavor! It doesn’t look like a lot of sauce because the veggies absorb some of it, but make no mistake, you can taste it in every bite!
- Never watery – If you’ve made my standalone zucchini casserole before, you know I won’t settle for anything less. This time I use a different method, but the texture is just as important. Don’t miss my tips below!
- Easy, healthy meal – The steps are straightforward, the ingredients are fresh and simple, and it’s packed with protein and veggies. Plus, it’s meal prep friendly, so you can even enjoy my chicken zucchini casserole on busy weeknights. You don’t need any sides, but you could start with a soup or salad, or finish off your meal with my summery cherry crisp.
Ingredients & Substitutions
Here I explain the best ingredients for my chicken zucchini casserole recipe, what each one does, and substitution options. For measurements, see the recipe card.
Main Ingredients:
- Chicken – I usually use boneless skinless chicken breast, but boneless chicken thighs also work. Cut the chicken into 1-inch pieces. Or if you’ve got leftover chicken bites, Instant Pot shredded chicken, or even a rotisserie chicken, feel free to use those — and save time by skipping the pan searing step.
- Vegetables – I used sautéed mushrooms, onions, and of course, zucchini. Yellow squash actually works just as well instead of zucchini. You can also toss in bell peppers or broccoli if you like.
- Olive Oil – For searing the chicken and sauteing the veggies. Avocado oil works just as well.
- Sea Salt & Black Pepper
VARIATION: Add garlic for more flavor!
I didn’t add garlic in my casserole, but feel free to add 2-4 cloves of minced garlic—just sauté them with the onions and mushrooms.
Cheese Sauce:
- Shredded Cheese – The star of my chicken zucchini casserole is the Swiss Gruyere cheese blend! I love the nutty, slightly sweet flavor. If you can’t find a blend, you can just shred both cheeses yourself. If you prefer a milder flavor, swap in a combo of parmesan and mozzarella cheese instead.
- Heavy Cream – This makes the sauce rich and creamy. If you’re looking for a lighter option, you can substitute with half-and-half or whole milk, but the sauce will be less thick.
- Chicken Broth – You can use my homemade chicken broth or a reduced-sodium store-bought version. If all you have is regular, I recommend using less salt on your chicken and veggies.
- Sour Cream – For more richness and tang. Greek yogurt works well as a substitute. Cream cheese can also work, but you might need a splash of extra cream, since it’s thicker.
How To Make Chicken Zucchini Casserole
I have step-by-step photos here to help you visualize the recipe. For full instructions with amounts and temperatures, see the recipe card.
- Season & dry the chicken. Place the chicken pieces in a large bowl and pat dry with paper towels. Season with salt and pepper.
- Cook the chicken. Heat olive oil in a large skillet over medium-high. Add the chicken pieces and sear, turning to brown all sides until cooked through. Transfer to a bowl and cover to keep warm.
- Sauté the mushrooms & onions. Add more olive oil to the pan, reduce the heat, and add the mushrooms and onions. Cook until the mushrooms are soft and there is no liquid in the pan.
- Cook the zucchini. Turn the heat to medium-high again, add the zucchini, and season with salt and pepper. Sauté until soft and slightly browned, then drain any remaining liquid. Transfer to the bowl with the chicken and set aside.
- Make the sauce. While your oven preheats, add the heavy cream and chicken broth to the same skillet. Scrape up any browned bits with a wooden spoon. Simmer for about 5 minutes, until the sauce coats the back of a spoon. Then, stir in shredded cheese, until melted.
- Assemble & bake. Pour the sauce into the bowl with the chicken and veggies. Mix to combine, then transfer the mixture to a small baking dish (I use this one and it’s the perfect size). Sprinkle more shredded cheese on top. Bake the chicken zucchini casserole until the cheese on top is melted. If you like it browned more (highly recommend!), place under the broiler.
My Recipe Tips
I’ve been making this chicken zucchini casserole since 2018, but I made some tweaks to the recipe recently to improve it. And I discovered some additional tips along the way:
- Browning and stovetop temp depends on your pan. I use cast iron and sometimes need to turn it down, but with nonstick you may need the heat even higher.
- Use lower heat if you don’t want your chicken to darken. I like mine golden, but you can choose medium heat if you like less browning.
- It’s important to cook down the zucchini and mushrooms enough and let all the liquid evaporate. If you don’t, the casserole will be watery. If the zucchini starts to brown too much, reduce heat to medium but continue cooking to get it tender. If it’s crisp, it will release water when you bake the chicken zucchini casserole.
- Drain the chicken and veggies if needed. Sometimes the veggies still release more moisture as they sit while I make the sauce. If this happens, drain them again before mixing in the sauce.
- Save time by multitasking. I cut the zucchini while the mushrooms and onions cook, then make the Gruyere cheese sauce while the oven preheats.
- Do not use a whisk to mix in the shredded cheese. The cheese will clump on the whisk. I’ve found that a wooden spoon works best for this.
- Salt the sauce to taste. I didn’t need additional salt in the sauce, but this will vary depending on the broth and cheese brands you use.
Storage & Meal Prep
- Store: Keep leftovers in an airtight container in the refrigerator for up to 3-4 days. The veggies do get more mushy, but the flavor is still great.
- Meal prep: This chicken and zucchini casserole does have several steps, but it’s a breeze if you prep ahead! You can either just do the chopping in advance, or assemble the whole thing and keep it in the fridge (for 1-2 days) until ready to bake.
- Reheat: Just pop it in the oven for 15-20 minutes at 350 degrees F. The microwave works for individual portions if you’re in a hurry.
- Freeze: The assembled casserole freezes well for up to 3 months. You can reheat it from frozen at 350 degrees F, but this takes a long time (at least 45 minutes), so I usually thaw it in the fridge overnight for quicker heating.
More Cheesy Casserole Recipes
If you’re a fan of easy, cheesy casseroles like this, you’ll love my others:
Tools I Use For This Recipe
- Casserole Dish – My favorite brand. This one is a little smaller than your standard baking dish, but it’s the perfect size for this recipe. You can use a larger one, but it will be less full.
- Cast Iron Skillet – You need a big skillet to fit all those veggies before they cook down! And I love my cast iron for the best browning and evaporating extra moisture.
Chicken Zucchini Casserole
This chicken zucchini casserole has a rich cheese sauce, plus more melty cheese on top! My easy cooking method keeps it from getting watery.
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Instructions
Tap on the times in the instructions to start a kitchen timer.
Cook The Chicken:
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Place the chicken pieces in a large bowl and pat dry with paper towels. Season with 1/2 teaspoon of salt and 1/4 teaspoon of pepper.
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Heat 1 tablespoon of olive oil in a 12-inch skillet over medium-high heat. Add the chicken pieces and sear for 5-6 minutes, turning every couple of minutes to brown all sides, until cooked through. Remove the chicken to a large bowl, cover to keep warm, and set aside.
Cook The Veggies:
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Add the remaining 1 tablespoon of olive oil to the pan and reduce heat to medium. Add the mushrooms and onions. Cook for 7-10 minutes, until the mushrooms are soft and there is no liquid in the pan.
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Increase heat to medium-high. Add the zucchini. Season the vegetables with the remaining 1/4 teaspoon of salt and 1/4 teaspoon of pepper. Saute, stirring occasionally, for about 10 minutes, uncovered, until the zucchini is soft and a little browned. Most (if not all) of the liquid should evaporate.
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Drain the veggies if any liquid remains and transfer to the bowl with the chicken. Set aside.
Make The Sauce:
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Preheat the oven to 400 degrees F (191 degrees C).
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While the oven preheats, add cream and chicken broth to the same skillet. Scrape the bottom of the pan with a wooden spoon to release any browned bits. Turn on the heat to medium-high and bring to a boil, then simmer for about 5 minutes, until thick enough to thinly coat the back of a spoon.
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Reduce heat to low. Stir 3 ounces of the shredded cheese into the pan, until melted.
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Remove from heat. Stir in the sour cream. If needed, season the sauce with salt and pepper to taste.
Assemble & Bake:
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If any additional liquid has formed in the bowl with the zucchini and chicken, drain it. Then, pour the sauce into the bowl with the chicken and veggies. Mix to combine.
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Transfer the mixture to a 10×7-inch casserole dish. Sprinkle the remaining 3 ounces of shredded cheese on top.
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Bake for about 10 minutes, until the cheese on top is melted. If desired, place under the broiler for 2-3 minutes to brown the cheese on top.
LAST STEP: Leave a rating to help other readers, or tag me @wholesomeyum on Instagram. I’d love to hear from you!
Maya’s Recipe Notes
Serving size: 1 cup
I provide nutrition facts as a courtesy. Have questions about calculations or why you got a different result? Please see my nutrition policy.
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© Copyright Maya Krampf for Wholesome Yum. Please DO NOT SCREENSHOT OR COPY/PASTE recipes to social media or websites. We’d LOVE for you to share a link with photo instead.
Chicken Zucchini Casserole
Gratitude Moment
I just got back from a trip to sunny San Diego and didn’t even realize how much I needed a “real” vacation until it hit me. I travel a lot, but it’s always go, go, go — and a lot of it is for work.
This time, a group of my girl friends all went together for a relaxing weekend. And unlike most of our family trips that are pretty planned out, we just did whatever we felt like last-minute. It was just what I needed — even if it meant coming back to a 12-hour recipe photo shoot the next day. 😉
I did bring back a “lovely” sunburn, because clearly I underestimated the California sun with my SPF. It was worth it.
108 Comments
Paula Mihalyfi
2Really yummy. Ended up using broccoli instead of zucchini and rotisserie chicken, it was Delicious. Enjoyed the cheese blend, found it at Trader Joe’s. Thanks for the recipe. Might try this in a pan that can go in the oven next time for even less dishes.
Cindy
1This was an easy meal. I used ground chicken, and added the garlic. It was quite good! Next time, I’ll experiment with adding some other herbs or spices to give it a little more flavor.
Maya | Wholesome Yum
0I’m glad you liked this, Cindy! Great idea with ground chicken, I bet that was totally different and delicious in its own way.
Andielinn
1Just a little tip…. if you have an Aldi nearby, my local Aldi carries bagged/shredded Swiss & Guyere for about $4. Not bad at all and it definitely made this dish just perfect!
Dee
0I made the recipe and it is very good. I made a few changes, I added garlic, ginger, and cumin. I also made noodles to go with it in the same bowl. They are 1 carb noodles per serving.
Wholesome Yum D
0Thanks for giving it a try, Dee! Your additions sound super flavorful and those low carb noodles sound like the perfect pairing.
Brenda Nesbitt
0I have put this in the rotation for zucchini season! Such a wonderful, tasty combination! Thank you.
Wholesome Yum D
0So glad to hear that, Brenda! Love that it’s earned a spot in your zucchini season rotation. Thanks for sharing!
Jodi cox
0This was delicious, I used smoked Gouda cheese, smoked cheddar cheese amazing 😋
Maya | Wholesome Yum
0Thank you, Jodi! Those cheeses sound amazing in this casserole.
Flo
0My favorite casserole! Thank you, Maya ❤️
Maya | Wholesome Yum
0I’m so glad it’s your fave, Flo! Thank you.
CP
0Excellent 👌 So glad I tried it 😁
Maya | Wholesome Yum
0Thank you! I’m glad, too!
Lauren
0I have made this 3 weekends in a row! Makes great leftovers. Super easy and tastes very fancy!
Marya
0This recipe was very tasty and delicious. I’m new to keto cooking and I love to try new recipes. Thank you for this one. My husband had a second helping.
Maya | Wholesome Yum
0Thanks, Marya! I’m glad both you and your husband enjoyed this casserole.
Cindy_VT
0We love casseroles and this is another wonderful recipe to add to the repertoire for zucchini season. The only tweak I made was to add a 1/2 teaspoon of rosemary because I didn’t think my chicken broth would be flavorful enough without it. Thanks so much for sharing it.
Susan
0It doesn’t say whether to take onions and mushrooms out of the pan before adding zucchini to the pan. Or do you add the zucchini to the already browned mushrooms and onions? Please clarify. Thank you!
Maya | Wholesome Yum
0Hi Susan, Yes, you add the zucchini to the already browned mushrooms and onions.
Susan
0It was delicious! I will definitely be making this again!
Deborah L.
0Made this tonight and it was a hit. Even though my husband normally complains about zucchini, he didn’t say anything about it being in the dish and gave it 4.5 stars out of 5, high praise from him! (I gave it 5 stars)
Maya | Wholesome Yum
0That’s awesome, Deborah! 4.5 is pretty good for someone who complains about zucchini, haha.
Veronica Alfonso
0This recipe was delicious, cooked and loved the fam loved it ! Thank you. Truly Amazing!!
Judy
0This recipe sounds delicious but I’m not a fan for mushrooms. What can I use instead?
Maya | Wholesome Yum
0Hi Judy, You could leave out the mushrooms and add an extra zucchini, or carrots would work well here.
Maya | Wholesome Yum
0Thanks, Veronica! I’m happy your whole family loved it.
Judy
0Made this for dinner a few days ago, because we had a bunch of courgettes coming in. It was super easy to do and a fairly quick prep of a meal. Loved the gruyere cheese! I did add mushrooms because we all love them. It got a thumbs up from all of us and we’ll definitely do it again.
Maya | Wholesome Yum
0Thank you, Judy! Yay perfect timing!
Lorna
0I love serving it with air fryer chicken thighs or pan-seared salmon. It’s incredibly versatile and easy to prepare. I often make extra and store leftovers in the fridge too.
Yam
0So good and easy to make! Love it! Thanks Maya!
Rosella
0I finally found the time to write a review for this amazing recipe!
I prepped all the veggies ahead of time, making the assembly a breeze the next day. We enjoyed it as a family dinner, and the leftovers were just as delicious. The casserole reheats wonderfully, maintaining its taste and creaminess. It’s now a favorite in our meal rotation, especially for those busy weeknights when we need something satisfying and easy to prepare.
Ginny
0I made this dish for 4 people and it was barely enough to serve all of us! The flavor was great however and I plan on making it again. This time there will be 8 adults and 2 babies. If I double the recipe will this be enough?
Wholesome Yum D
0Hi Ginny, I can’t say for sure because every person eats a different amount. Feel free to 1.5x or even double the recipe if you don’t think it will be enough.
Cathy
0The ingredient list states 3 oz. cheese for the sauce, but the instructions state to add 2 oz. Which one is correct? The ingredient list for the topping states 4 oz and the instructions state “remaining” cheese, which I can only assume means the 4 oz, or does this mean 5 oz as that is what would be remaining?
Wholesome Yum D
0Hi Cathy, Step 10 should be 3oz.
Victoria
0YUM-OH! What a delicious dish! I at least doubled the recipe and it turned out so great! I substituted white wine for chicken broth and added sun-dried tomatoes. It ended up being a little “saucy” (some people call it thin…), so I served it in a shallow bowl with both a fork and a spoon! I grated my own gruyere and swiss and the sauce was super tasty. Took some time to cut and cook everything, especially because there were three rounds of cooking in the same pan, but I would definitely make it again.
Holly L.
0I made this and took it to a pot luck. It was a huge hit. Very decadent and easy to make. I love comfort casseroles and this is! Thanks Maya for another great recipe!!
Linda Smith
0Delicious casserole and I’m not normally a zucchini fan… gruyere sauce is so good!
Andielinn
0This was SO good!!!! We’ve been living a keto lifestyle for 3.5 years and we’re at the point where we’re looking for new, different flavors. This checked those boxes! Our son, who is not keto, loved it but said he’d love it even more over pasta. DEFINITELY a repeat in our house! Thank you!!!!
Mischa (down in TX)
0Made this for dinner and it was a huge hit with my husband who usually doesn’t like zucchini. I didn’t have cream, so I subbed cream of chicken soup for the cream and the broth. Thanks for a great recipe.
Carrie
0This was a WIN! I saw some people saying it was a little runny but I thought it was delicious! Thanks for all the little tips that make this so easy. The only thing I would do differently next time is start the zucchini sauté before adding onions and mushrooms.
Elizabeth
0I used poached, shredded chicken and substituted blue cheese and cream cheese. Topped with oil-rubbed kale. Delicious!
Rebecca
0Made this tonight for dinner, followed the recipe exactly, but the cheese sauce didn’t thicken at all, added more cheese, nothing. Cheese sauce was so thin
Wholesome Yum D
0Hi Rebecca, I’m not sure why it was thin for you, a possible reason is that the zucchini needed to be stir fried for longer to get rid of extra moisture, it will release water when baking later and make the sauce too thin.
Gloria W Parrish
0I made this this past weekend and my husband loved it. I used a little cream cheese and shredded mozzarella cheese since I did not have gruyeer cheese, though.
Mandie
0This is my favorite recipe! I make it put portions in the fridge and have it for lunch. I make mine with Swiss. I like it because it doesn’t eat up all my carbs for a day.
Wanda Kjar-Hunt
0My husband absolutely loved this recipe & I did too. He wanted me to give you 10 stars!!
He has said he doesn’t mind eating Low carb as long as the food is good. He said this is a top 3 of what I’ve made these past 3 months!
I used Swiss & Italian cheeses as it’s what I had on hand.
Matty
0This was a disaster and a total waste of a very expensive cheese (Gruyere).
Cooked it two times: 1) followed recipe to a T, veg got mushy instead of crisp, 10 minutes in the oven left the meat uncooked. Meal went in the bin. 2) cooked veg separately, as another reviewer pointed out, left the meal way longer in the oven (as yet another reviewer has pointed out), cooked the chicken way longer and ended up with an OK meal and a kitchen full of dishes to wash.
Will never do again!!
Wholesome Yum M
0Hi Matty, Sorry this recipe didn’t turn out as expected. There isn’t a way to make this recipe with ‘crisp’ vegetables. If you don’t work out enough water from the zucchini while it’s on the stovetop, you will end up with a watery casserole.
Rex
0Actually, this was really good. I made two tweaks: sautéed the onions and mushrooms Worcestershire sauce and then added a quarter cup of red wine with the chicken, boiling the wine down before doing the cream and chicken broth. Then, after the cheese melted on top in the oven, sprinkled some bread crumbs on top then baked. Really good flavors and some textures,
Shanna
0My whole family loved this recipe! It was incredibly good, and easy to make. I will be making this often and am looking forward to making this when we have people over.
Karen
0Loved the flavor! I would do the veggies separately. The onions began to burn and the mushrooms weren’t dehydrated enough. I removed them and did the zucchini separately. I had a surplus of canned white chicken. I used two 10 oz cans. My family likes more meat. It was a bit soupy, but there was nothing left!
MARY
0Made this last night, it was yummy. I used yellow squash since it’s all I had but figured it was pretty close in texture and taste as zucchini since they’re both summer squash. Will make again with zucchini.
Only other change than that was I added red pepper flakes to both the veggies as they were cooking and the sauce (cream, broth) since we like it spicy.
One question – in the ingredient list it says 3 oz shredded cheese and in the instructions it says 2 oz. Just wondering which is correct? I used 3 oz and it came out well.
Wholesome Yum M
0Hi Mary, It’s 3 ounces! Enjoy!
Jessica
0This turned out pretty good, but I think my sauce was too thin, which made the zucchini get soggy in the leftovers. Not sure I would make it again. Also I prefer to split this into only 6 servings, 8 seemed too small.
Dana
0LOVE, LOVE, LOVE this recipe!!! I just made it and it is fabulous! Thank you so much, your recipes never disappoint. It was so easy and will become part of our rotation. I just have one question. When it’s done, is the liquid in the bottom of the casserole dish supposed to be thin? It was great, I just wasn’t sure if I made a mistake along the way. Thanks again!
Wholesome Yum M
0Hi Dana, Yes, that’s fine. There aren’t any thickeners or binders in the cheese sauce, so it’s normal for a small amount of separation to occur.
Mary
0When do you cook the chicken? The end says put in oven for 10 minutes. That does not seem like enough time for the pieces to cook.
Wholesome Yum M
0Hi Mary, The chicken is cut into bite-sized pieces and sauteed on the stovetop (see step 6). It will then bake in the oven (step 12). As long as the chicken pieces are cut into bite sized pieces, this is enough time for them to cook through. Enjoy!
Jessica
0I used chicken I made in the air fryer and I only used 2 zucchini. I wanted to use cheeses I had on hand so I used smoked Gouda and Mexican cheese blend. The sauce was amazing! It would make an awesome Mac & cheese!
Kara
0I was nervous at first because my zucchini was taking FOREVER to lose all its moisture. But we got there after about 20 mins! The zucchini sort of fell apart, but in the end it didn’t affect the casserole at all! I did also add about 1/4tsp of xanthan gum to the sauce at the end to help thicken it before mixing with the chicken and veggies. I think the pre-shredded gruyere I bought may have had a coating on it to maintain freshness that caused it to not melt as easily — thus the sauce didn’t thicken well. But the little bit of xanthan gum worked perfectly! Despite warning my husband that the serving size was 1/8 of the casserole, he couldn’t help himself and went back for seconds and thirds! He wouldn’t stop gushing about how delicious it was! He’s been eating the (cold) leftovers for lunch each of the last two days
Thanks for another great recipe that I’m sure to make again and again!
kim nedz
0Hello, Can I make this in a crock pot?
Wholesome Yum M
0Hi Kim, This recipe would turn out too watery in a crockpot. The best way to make this dish is in the oven.
Lois
0I’m thinking that I might substitute shredded rotisserie chicken from the deli instead of cooking from raw. What do you think?
Wholesome Yum M
0Hi Lois, Yes that will work great! Enjoy.
Vicky
0I had my eye on this recipe for over 2 weeks. It was definitely worth the wait – my husband and I devoured it! Thank you so much for posting this – absolutely delicious. I really think the gruyere cheese made the taste so distinctive so if you can possibly splurge, do it!
Kathy Lorenzato
0Good flavor, but I’m guessing that Jarlsberg doesn’t make a sauce like Gruyere would. I couldn’t find Gruyerre and when I put in the shredded Jarlsberg the cheese just coagulated on the whisk. I hard a hard time removing it from the whisk! So I got a very thin sauce. Any ideas on what I can use when I can’t find Gruyere? Thanks.
Wholesome Yum M
0Hi Kathy, Jarlsberg should work fine. The cheese should be melted at low heat, otherwise it will start to clump or oil will separate from it. If you can find Emmental, that’s another great melting cheese. The sauce will be thicker when it comes together properly.
Jessie
0If baking this from frozen, what temp for how long? Thanks!
Wholesome Yum M
0Hi Jessie, Thaw at room temperature. Bake at 400 degrees for 10 minutes or until heated through and the cheese melts.
Leigh
0I made this exactly as given in the recipe and it was DELICIOUS! I cooked out the liquid from the veggies as directed and the casserole turned out just fine. Grueyere is a little on the pricey side for me, but a combo of Swiss and Havarti turned out great. The casserole re-heats well – just had it for lunch!
Thanks so much! This will be a go-to for me!
Susan R Anderson
0Could you sub shrimp instead of chicken?
Wholesome Yum A
0I don’t see why not, Susan! You might want to bake for less time to avoid overcooking them.
Allison Dabney
0This was really good! I usually don’t like to read the reviews of the people who made a million changes but I kind of winged this one with what I had available. I had leftover grilled chicken so used this instead of cooking additional chicken. I had one yellow squash and one zucchini. To make up for this and to add a little carb-like texture, I used a pack of the shirataki “rice.” Everything else I did exactly as the recipe was written. It was fantastic. I will be making this again! Thank you for the inspiration!
Adriana
0Both my kids (3 yr old & 17 yr old) gobbled this up! I used extra sharp cheddar & bell peppers since I didn’t have mushrooms or swiss cheese. Served it along crisp greens and homemade balsamic vinaigrette and it was delicious