Zucchini and Squash Casserole
Sep 10, 2026
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Made with fresh yellow squash, zucchini, an easy cream sauce, and plenty of cheese, this Zucchini and Squash Casserole is a comforting side dish that tastes just like dinner at Grandma’s. Creamy, cheesy, easy to make, and always a hit with the whole family!
My Kids Devour This Squash and Zucchini Casserole!
We all know that some kids will happily munch on just about any vegetable, while others can be a little more hesitant when it comes to anything green… or squash-like. Can I get a witness?
But this delicious squash and zucchini casserole might just win them over! It’s layered with melted cheese, a creamy sauce, tender zucchini and yellow squash, and a crispy Panko topping. Even picky eaters will have a hard time saying no!
Recipe Ingredients
- Fresh Zucchini and Yellow Squash: Slice into ½-inch-thick rounds, or spiralize if you prefer.
- Butter: Use 1 stick of unsalted butter, softened to room temperature.
- Flour: All-purpose flour thickens the creamy sauce.
- Milk: I use regular milk, but lower-fat milk works, too.
- Italian seasoning: Use your favorite Italian seasoning blend, or swap in another herb and spice blend you love.
- Fresh Garlic: Mince or press the garlic before adding it to the sauce.
- Olive Oil: For sautéing the zucchini and squash and drizzling over the casserole. Avocado oil or another neutral cooking oil will also work.
- Salt and Pepper: Season to taste.
- Mozzarella and Parmesan: I use shredded mozzarella and grated Parmesan for the cheesy layers, but you can swap in your favorite shredded cheese.
- Panko: Regular or gluten-free Panko breadcrumbs will work.
How to Make Zucchini and Squash Casserole
- Prep: Preheat the oven to 375˚F. Grease a 9×13-inch baking dish with butter and set aside. Cut the zucchini and yellow squash into ½-inch thick slices. Place the sliced vegetables in a colander, sprinkle with salt, and let them stand to drain.
- Make the cream sauce: Melt the butter in a saucepan over medium heat. Whisk in the flour and cook for 2 minutes, whisking constantly. Slowly add the milk and Italian seasoning, whisking constantly until smooth. Simmer for 8 to 10 minutes until the sauce thickens.
- Dry and season the vegetables: Use paper towels to pat the zucchini and squash completely dry. Transfer them to a large bowl and toss with the garlic, a drizzle of olive oil, and a little salt and pepper.
- Sauté the veggies: Heat the remaining tablespoon of olive oil in a large skillet over medium-high heat. Add the vegetables and cook for about 3 minutes, stirring frequently, until they just begin to soften. Remove from the heat, drain any excess juices, and set aside.
- Layer the casserole: Spoon ¾ cup of the cream sauce over the bottom of the prepared baking dish. Arrange half of the sautéed zucchini and squash over the sauce, then sprinkle with 1 cup of mozzarella and ⅓ cup of Parmesan. Repeat the layers with the remaining vegetables, mozzarella, and Parmesan. Sprinkle the Panko over the top and drizzle with a little olive oil.
- Bake: Bake for 30 to 35 minutes, or until the top is golden brown and the casserole is bubbling around the edges. Remove from the oven and let cool for 10 minutes before serving with a garnish of fresh parsley and grated Parmesan.
Recipe Tips
- Don’t overcook the squash: Sauté the squash and zucchini just until they begin to soften. They’ll continue cooking in the oven, so overcooking them in the skillet can make the casserole mushier.
- Taste and adjust the seasoning: The vegetables, cream sauce, and cheeses all add flavor to the casserole, so season each component properly. Taste the sauce and vegetables before assembling the casserole, and adjust the salt and pepper as needed.
- Squash options: If you don’t have both yellow squash and zucchini on hand, you can make this casserole with just one or the other.
Easy Variations
- Try different seasonings: Swap the Italian seasoning for Cajun seasoning for a little kick, or try lemon pepper, seafood seasoning, herbes de Provence, or your favorite garlic and herb blend.
- Vegetable options: Use this same basic recipe to make a broccoli and cauliflower casserole. Simply replace the squash with lightly steamed broccoli and cauliflower.
- Make it a main dish: Enjoy this zucchini casserole as a vegetarian dinner, or make it heartier by adding layers of cooked Italian sausage, chicken, or diced ham.
What To Serve with Zucchini Squash Casserole
- Seafood: Pair it with Old Bay roasted salmon for an easy dinner. The bold seasoning is great with the creamy, cheesy casserole.
- Chicken: These pan-seared Cajun butter chicken thighs are juicy, flavorful, and go with just about anything.
- Dessert: Finish dinner with Southern banana pudding, made with layers of creamy vanilla pudding, bananas, and fluffy meringue.
Zucchini and Squash Casserole
Easy zucchini and squash casserole made with tender yellow squash and zucchini, baked in a rich cream sauce with plenty of cheese. This creamy, cheesy squash casserole is a comforting vegetable side dish for family dinners, potlucks, Thanksgiving, and holiday meals.
Video
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
- 3½ cups milk
- 2 teaspoons Italian seasoning
- 4 cloves garlic, minced
- 1½ tablespoons olive oil, divided
- salt and freshly ground black pepper, to taste
- 3 cups shredded mozzarella cheese OR shredded Parmesan 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: Preheat the oven to 375˚F.
- Prep: Grease a 9×13-inch baking dish with a little butter and set aside. Cut the zucchini and yellow squash into ½-inch thick slices. Place in a colander, sprinkle with salt, and let drain.
- Make the cream sauce: Melt the butter in a 2-quart saucepan over medium heat. Whisk in the flour and cook for 2 minutes, continuing to whisk. Slowly add the milk and Italian seasoning, whisking constantly until smooth. Simmer for 8 to 10 minutes, whisking frequently, until the sauce thickens.
- Season the vegetables: Use paper towels to pat the squash and zucchini as dry as possible, then transfer them to a large bowl. Add the garlic, ½ tablespoon of olive oil, and salt and pepper to taste. Toss to combine.
- Sauté: Heat the remaining 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the squash and zucchini and cook for 3 minutes, or until they just begin to soften, stirring frequently. Remove from the heat, drain any excess juices, and set aside.
- Layer: Spoon ¾ cup of the cream sauce over the bottom of the prepared baking dish. Arrange half of the squash mixture over the sauce. Sprinkle with 1 cup of mozzarella and ⅓ cup of Parmesan. Add the remaining squash mixture, then cover with the remaining cream sauce and sprinkle with the remaining mozzarella and Parmesan. Sprinkle the Panko breadcrumbs over the top and drizzle with a little olive oil.
- Bake: Bake for 30 to 35 minutes, or until the top is golden brown and the casserole is bubbling around the edges.
- Cool, then serve: Remove from the oven and let cool for 10 minutes. Top the casserole with fresh parsley and grated Parmesan. Serve warm.
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
Nutritional info is an estimate and provided as courtesy. Values may vary according to the ingredients and tools used. Please use your preferred nutritional calculator for more detailed info.
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How to Store and Reheat Leftovers
- Refrigerate: Cover the leftovers tightly or transfer them to an airtight container and refrigerate for up to 4 days.
- Freeze: Transfer the cooled casserole to freezer-safe containers or freezer bags, removing as much air as possible before sealing. Freeze for up to 2 months for the best quality.
- Reheat: Place the desired portion in an oven-safe dish and bake at 350˚F until heated through. Frozen leftovers will take longer to reheat, so make sure the casserole is hot all the way through before serving.
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!
I am very glad you enjoyed it! Thank YOU! 🙂
How much milk?
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.
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.
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!!!
That’s great to hear! I am very glad everyone enjoyed it! Thank you for chiming in! 🙂
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!
That’s great! I am very happy everyone enjoyed it! Thank YOU! 🙂
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!
I’m very glad you enjoyed it! Thank YOU! 🙂
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.
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?
can I make this a day ahead and then bake the next day?
Looking for the same answer! Did you make ahead and bake next day?
Rather a labor-intensive recipe with lack-luster results. The sauce was far too much and I used five squash and zucchini and needed to be seasoned. This could be prevented with better proportion instructions for the squash and zucchini (cups or ounces). Salting zucchini and squash also makes them turn to mush when the water is secreted so the extra cooking in a pan is unnecessary. Mozzarella is also a really wet cheese. It just didn’t work all together. The flavor was off, consistency was off and just not something I’d make again.