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Cheesy Zucchini and Squash Casserole

Using fresh yellow squash, colorful zucchini, an easy cream sauce, and plenty of cheese, this Cheesy Zucchini and Squash Casserole feeds a houseful and tastes just like dinner at Grandma’s. The whole family will love it!

overhead picture of squash and zucchini casserole in baking dish

My Kids Devour this Easy Squash Casserole!

So we all know that, while some kiddos will happily munch raw or cooked veggies of all kinds… many will be a bit leery (or downright rebellious) of anything, you know… green. Or squash-like. Can I get a witness?

But, this delicious squash casserole beats the odds! Even picky eaters will love the layers of melted cheese, creamy sauce, tender rounds of zucchini and yellow squash, and crunchy panko topping!

Recipe Ingredients

  • Fresh Zucchini and Squash: Cut these into ½-inch thick slices, or spiralize them if you prefer.
  • Butter: You’ll need one stick of unsalted butter at room temperature.
  • Flour: You’ll need ½ a cup of all-purpose flour for the cream sauce.
  • Milk: I use regular milk, but you can definitely substitute lower fat milk.
  • Seasoning Blend: I use 2 teaspoons of an Italian seasoning blend.
  • Fresh Garlic: Mince or press the garlic.
  • Olive Oil: For sautéing the squash and zucchini, plus more for drizzling.
  • Salt and Pepper: Season to taste.
  • Mozzarella and Parmesan: You’ll need 3 cups of mozzarella cheese and 1 cup of parmesan cheese for layering in the casserole.
  • Panko: Regular Panko or gluten-free will work.
  • Chopped Fresh Parsley and Grated Parmesan: For the garnish.
sauteeing spiralized zucchini in a black frying pan

How to Make Cheesy Zucchini and Squash Casserole

  1. Prep the Oven, Baking Dish, and Veggies. Preheat the oven to 375˚F. Grease a 9×13 baking dish with butter and set aside. Cut or spiralize the zucchini and yellow squash; place in a colander, sprinkle with salt and let stand to drain.
  2. Make the Cream Sauce. Melt the butter in a saucepan over medium heat. Whisk in the flour; continue to whisk and cook for 2 minutes. Slowly add in the milk and Italian seasoning, whisking constantly until smooth. Simmer the sauce for 8 to 10 more minutes, whisking frequently until it thickens.
  3. Dry and Season the Drained Veggies. In the meantime, use paper towels to pat dry the squash and zucchini as much as you can, and then place it in a large bowl. Add the garlic, a drizzle of olive oil, and a little bit of salt and pepper; toss to combine.
  4. Sauté the Veggies. Heat the remaining tablespoon of olive oil in a large skillet over medium-high heat. Add the squash mixture to the hot oil and cook for 3 minutes, or until it just starts to soften, while stirring frequently. Remove from the heat, drain any juices, and set the sautéed veggies aside.
  5. Layer the Casserole. Spoon ¾-cup of the cream sauce over the bottom of the buttered baking dish. Arrange ½ of the squash mixture over the cream sauce, then sprinkle with 1 cup of the mozzarella cheese and ⅓ cup of the parmesan cheese; repeat the layers a second time. Finally, sprinkle panko crumbs over the top and drizzle with olive oil.
  6. Bake. Bake the assembled casserole for 30 to 35 minutes, or until the top is golden brown. Remove from the oven and let it cool for 10 minutes. Garnish with parsley and parmesan cheese and serve.
  7. Enjoy!
overhead shot of prepped casserole with spiralized zucchini and squash

Tips for Success

  • Don’t Overcook the Squash: Be sure to sauté the squash and zucchini only until it begins to soften because it will still have to bake. Overcooking in the sauté stage will create a mushier texture in the finished dish.
  • Adjust Seasonings Frequently: Since this dish contains seasoned vegetables, a cream sauce, and two kinds of cheese, be careful about over-seasoning and under-seasoning. Taste the sauce and veggies at least twice to make sure that all the components taste right individually. Doing this helps make sure your finished casserole is correctly seasoned.
  • Choose One: If you don’t have both yellow squash and zucchini available, feel free just to use one or the other!
overhead close up shot of baked zucchini squash casserole

Variation Ideas!

  • Cajun Spice: Try substituting a Cajun seasoning blend for the Italian blend, but be careful to use less salt if your blend already includes salt. (Also, be aware that Cajun blends can be quite spicy; you may wish to add less than the two teaspoons called for in the original recipe.)
  • Veggie Ideas: You can also use this basic recipe and technique to create a broccoli and cauliflower casserole! Substitute very lightly steamed broccoli and cauliflower for the squash and zucchini.
  • Main-Dish Magic: Want to make this a main dish? Try adding layers of cooked Italian sausage, cooked chicken, or diced ham to the casserole. So tasty!

What Goes with Zucchini and Squash Casserole?

  • Salmon: Try this casserole as a side to accompany a beautiful entree of Old Bay Roasted Salmon. The salmon’s classic seasoning will pair perfectly with the cheesy vegetables!
  • Chicken: These Pan-Seared Cajun Butter Chicken Thighs are an easy recipe that goes with just about anything, especially a creamy, garlicky side like Cheesy Squash Casserole!
  • Banana Pudding: Thanks to its light, vanilla-accented flavor profile and foamy meringue topping, this tasty traditional Southern Banana Pudding is a fantastic follow-up to squash casserole.
scooping out zucchini squash casserole from baking dish

How to Store and Reheat Leftovers

  • To refrigerate. Cover leftovers tightly in an airtight container and store in the refrigerator for up to 4 days.
  • To freeze. Place in freezer bags or other freezer-safe containers, leaving as little air in the container as possible before sealing.
  • To reheat. Place the desired portion of casserole in an ovenproof dish. Bake at 350˚F until heated through. Reheating will take longer for frozen leftovers, so check carefully before eating.
overhead picture of squash and zucchini casserole in baking dish
Print Recipe
4.79 from 14 votes

Cheesy Zucchini and Squash Casserole

Using fresh yellow squash, colorful zucchini, an easy cream sauce, and plenty of cheese, this Cheesy Zucchini and Squash Casserole feeds a houseful and tastes just like Thanksgiving at Grandma’s. The whole family will love it!
Prep Time10 mins
Cook Time40 mins
Total Time50 mins
Course: Side Dish
Cuisine: American
Keyword: cheesy casserole, easy casseroles, easy dinner idea, healthy dinner ideas, squash and zucchini casserole, vegetarian casserole
Servings: 6 servings
Calories: 463kcal

Equipment

  • Stove
  • Oven

Ingredients

  • 2 large zucchini, cut into ½-inch thick slices OR spiralized
  • 2 large yellow squash, cut into ½-inch thick slices OR spiralized
  • 1 stick (8 tablespoons) unsalted butter, at room temperature
  • ½ cup all-purpose flour
  • 3 ½ cups milk
  • 2 teaspoons Italian Seasoning
  • 4 cloves garlic, minced
  • 1 ½ tablespoons olive oil, divided
  • Salt and freshly ground pepper, to taste
  • 3 cups shredded mozzarella cheese, divided
  • 1 cup grated parmesan cheese, divided
  • 1 cup panko crumbs
  • Olive oil, for drizzling
  • Chopped fresh parsley, for garnish
  • Grated parmesan cheese, for garnish, optional

Instructions

  • Preheat oven to 375˚F.
  • Grease a 9×13 baking dish with a bit of butter and set aside.
  • Cut or spiralize the zucchini and yellow squash; place in a colander, sprinkle with salt, and let drain.
  • In the meantime, melt the butter in a 2-qt. saucepan set over medium heat.
  • Whisk in the flour; continue to whisk and cook for 2 minutes.
  • Slowly add in the milk, stir in Italian seasoning, and continue whisking constantly until smooth.
  • Simmer and whisk frequently for 8 to 10 minutes, or until sauce thickens.
  • Meanwhile, using paper towels, pat dry the squash and zucchini as much as you can and then place in a large bowl. Add garlic.
  • Add 1/2 tablespoon olive oil to the vegetables and season with salt and pepper to taste; toss to combine.
  • Heat remaining 1 tablespoon olive oil in a large skillet set over medium-high heat.
  • Add squash and zucchini to the hot oil and cook for 3 minutes, or until it just starts to soften; stir frequently. Remove from heat, drain, and set aside.
  • Spoon ¾-cup of the prepared cream sauce over the bottom of the buttered baking dish.
  • Arrange ½ of the squash mixture over the cream sauce.
  • Sprinkle with 1 cup of the mozzarella cheese and ⅓ cup of the parmesan cheese.
  • Add the rest of the squash mixture and cover with the rest of the cream sauce, then sprinkle with remaining cheeses.
  • Sprinkle panko crumbs over the top and drizzle with olive oil.
  • Bake for 30 to 35 minutes, or until top is golden.
  • Remove from oven and let cool 10 minutes.
  • Garnish with parsley and parmesan cheese. Serve.

Nutrition

Calories: 463kcal | Carbohydrates: 29g | Protein: 27g | Fat: 27g | Saturated Fat: 14g | Cholesterol: 73mg | Sodium: 748mg | Potassium: 640mg | Fiber: 2g | Sugar: 12g | Vitamin A: 1026IU | Vitamin C: 23mg | Calcium: 681mg | Iron: 2mg

34 Comments

  • Sara Welch
    December 1, 2020 at 10:36 pm

    5 stars
    Needed some more dinner ideas for dinner this week and this hits the spot! Adding this to my dinner line up; looks too good to pass up!

    Reply
    • Katerina Petrovska
      December 3, 2020 at 6:53 pm

      I hope you enjoy it! Thank YOU! 🙂

      Reply
  • Amanda
    December 1, 2020 at 11:01 pm

    5 stars
    I loved this dish, kids enjoyed it as well, Thank you so much for sharing!

    Reply
    • Katerina Petrovska
      December 3, 2020 at 6:51 pm

      Thank YOU! I am very glad you enjoyed it! 🙂

      Reply
  • Vikki
    December 2, 2020 at 5:48 am

    5 stars
    Always on the lookout for easy recipes — especially casseroles, I love making them — and this one hits it out of the park! So yummy and easy

    Reply
    • Katerina Petrovska
      December 3, 2020 at 6:49 pm

      I am very glad you enjoyed it! Thank YOU! 🙂

      Reply
  • Toni Dash
    December 2, 2020 at 4:59 pm

    5 stars
    It was really a huge hit at my house! I can’t wait to make it again!

    Reply
    • Katerina Petrovska
      December 3, 2020 at 6:49 pm

      I am very glad you enjoyed it! Thank YOU! 🙂

      Reply
  • Catalina
    December 2, 2020 at 6:58 pm

    5 stars
    Sounds like an amazing and delicious casserole! I need this!

    Reply
    • Katerina Petrovska
      December 3, 2020 at 6:46 pm

      I hope you enjoy it! Thank YOU! 🙂

      Reply
  • Patricia @ Grab a Plate
    December 3, 2020 at 1:41 pm

    5 stars
    So cheesy and so good! I love recipes like this that include squash, and I love the zucchini, too! Wonderful!

    Reply
    • Katerina Petrovska
      December 3, 2020 at 6:45 pm

      Thank you so much! I hope you enjoy it! 🙂

      Reply
  • Beth
    December 3, 2020 at 3:08 pm

    5 stars
    This looks so delicious and yummy! My husband and kids are going to love this recipe! So excited to give this a try!

    Reply
    • Katerina Petrovska
      December 3, 2020 at 6:43 pm

      I hope you enjoy it! Thank YOU! 🙂

      Reply
  • Bunni
    December 8, 2020 at 8:14 pm

    In the oven now – but easy? NOT! 10 min prep? NOT! I did add sausage to it that took time but to cut the squashes, (would be helpful to have cup measurements for amount of cut squash instead of ‘large’), do the white sauce, grate the cheeses (note to self – get pre-grated mozzarella) it was probably 45 minutes of prep. I am a relatively accomplished cook, too. Yes, once all of that was done it was 10 minutes to get it assembled and into the oven. Looks delicious so hope it tastes that way also! Thanks…

    Reply
    • Dinorah Mejeur
      June 21, 2021 at 1:43 pm

      I agree with you! Assembling was the only quick part, the rest took a good amount of time and I used already shredded mozzarella. I hope this turns out good, It looked too cheesy, especially for the amount of squash and I actually used 3 and 3. I can’t imagine if I would have use only 4 squashes. I also added cooked chicken and I’m glad I did because just the veggies wouldn’t have been enough for all that cheese and cream. But we will see how it tastes. 15 more min to go in the oven 🤞

      Reply
    • Barb
      August 1, 2021 at 11:47 am

      3 stars
      This was not a quick dish to make ! I wish there was an amount of zucchini and squash , example , how large is. Large zucchini ? Put a cup amount and I would feel better ! It was tasty in the end, but not a weeknight dish !

      Reply
  • D Johnson
    January 31, 2021 at 6:26 am

    5 stars
    This recipe was incredible! Best casserole I’ve ever made or tasted. It took me almost two hours total start to finish, so dinner was late, but it was worth it. If I was a better cook I think it could have been done in an hour and a half. We added some ground beef from leftover tacos the night before on top of the first layer of squash. Excellent. I didn’t know squash could be so delicious. Thanks so much for the recipe!

    Reply
    • Katerina Petrovska
      February 2, 2021 at 4:24 pm

      That’s great to hear! I am very glad you and your family enjoyed it! Thank YOU! 🙂

      Reply
  • AmberD
    June 12, 2021 at 8:13 am

    Can this be made ahead of time?

    Reply
  • Shannon
    July 6, 2021 at 4:25 pm

    5 stars
    Great recipe! For those saying prep took to long… get a mandolin! You will zip through the zucchini and squash in minutes! I sliced mine right into a frying Pan, salted and allowed it to sit.. added the garlic and olive oil and sautéed.. placed in colander to drain while I made the sauce which was quick and easy as well! Having the right tools always speeds up the process! I am about to bake mine now and can’t wait to try it!

    Reply
    • Katerina
      July 15, 2021 at 3:25 pm

      I am very glad you enjoyed it! Thank YOU! 🙂

      Reply
  • RONALD
    July 31, 2021 at 10:38 am

    How much milk?

    Reply
    • Katerina
      August 1, 2021 at 7:14 am

      Hi!
      It’s 3½ cups milk. All that information is in the recipe card located towards the bottom of the post and right above the “comments” section.

      Reply
  • Jenelle DesMarais
    August 10, 2021 at 8:31 am

    4 stars
    I used 2 larger zucchini and what summer squash I had and used a mandolin per other’s suggestions. I already had shredded some mozzarella so it all came together pretty quickly. I also had some “pizza” seasonings on hand and added those in with the Italian seasonings. It seemed a bit bland to me – it was like a white sauce vegetable lasagna minus the noodles and it was close to being really good but just fell a little flat. Perhaps it’s the not knowing how many cups of squash is needed, or exactly what the proper amount of salt/pepper should be (I thought I salted the heck out of the squash before letting it drain in the colander so was afraid to add more while cooking and really don’t want to taste-test partially cooked squash for verification of the level of salt that is appropriate), but it lacked something. I may make this again but would have to season it quite a bit more.

    Reply
  • Jennifer
    August 14, 2021 at 3:55 pm

    5 stars
    This was a hit for my family for supper my husband hates casserole but he told me I can make this one again lol!! I added onion and ham to this recipe it was perfect well except some of the veggies were not all the way done I shoulda cooked it a little more but it was awesome otherwise!!!

    Reply
    • Katerina Petrovska
      August 25, 2021 at 10:34 am

      That’s great to hear! I am very glad everyone enjoyed it! Thank you for chiming in! 🙂

      Reply
  • K
    August 14, 2021 at 11:26 pm

    5 stars
    Okay, so I got nervous because I realized mid-recipe that I had cut up a BUTTERNUT squash and not a summer squash (rookie mistake) BUT I made the recipe anyway, added some diced onions, went light on the parmesan cheese and used Italian bread crumbs with melted butter mixed in for the topping and let me tell you… I brought this dish to a party and EVERYONE loved it, including my sister who said she was “zucchinied out.” In other words, was a hit. So if you’re looking for alterations, give this a shot!! I liked it too. 🙂 Sweet and savory as well as creamy!

    Reply
    • Katerina Petrovska
      August 25, 2021 at 10:33 am

      That’s great! I am very happy everyone enjoyed it! Thank YOU! 🙂

      Reply
  • Natalie
    August 18, 2021 at 11:49 am

    5 stars
    Very tasty side dish. I sautéed some baby portabella mushrooms along with the zucchini and summer squash mixture. My husband says it tastes like green bean casserole!

    Reply
    • Katerina Petrovska
      August 25, 2021 at 10:01 am

      I’m very glad you enjoyed it! Thank YOU! 🙂

      Reply
  • Mike
    August 21, 2021 at 10:37 am

    How many servings (approximate size) does this make and what size baking dish is required?

    I badly want to make this but need to scale it to 4 servings.

    Reply
  • Lindsay
    September 4, 2021 at 8:00 pm

    Hi! I am not sure what I did wrong but mine doesn’t look anything like your photo? The panko crust is thick (this part was yummy and I used the right measurements) but the photo looks like it has no panko and more like a egg breakfast casserole. My sauce kinda clumped up and resembled a sausage biscuit gravy if that makes sense and it wasn’t super thick
    Before the layering? Any ideas?

    Reply
  • Ellen morton
    September 9, 2021 at 9:58 am

    can I make this a day ahead and then bake the next day?

    Reply

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