Creamy Cheddar Zucchini and Yellow Squash Casserole

Using fresh yellow squash, vibrant zucchini, a simple cream sauce, and plenty of cheese, this Cheesy Zucchini and Squash Casserole serves a crowd and tastes like a classic family dinner. It’s comforting, easy to prepare, and a favorite with kids and adults alike.

My Kids Devour this Easy Squash Casserole!

Some children turn their noses up at vegetables, especially anything green or squash-shaped. This casserole sneaks tender slices of zucchini and yellow squash into layers of creamy sauce and melted cheese, finishing with a crunchy panko topping—perfect for picky eaters.

The combination of mild squash, garlicky cream sauce, and a mix of mozzarella and parmesan creates a rich, familiar flavor that appeals to the whole family.

Recipe Ingredients

• Fresh zucchini and yellow squash: Slice into ½-inch rounds or spiralize, as preferred.
• Unsalted butter: 1 stick (8 tablespoons) at room temperature for the sauce and greasing the dish.
• All-purpose flour: ½ cup to thicken the cream sauce.
• Milk: 3½ cups; use regular or a lower-fat option if desired.
• Italian seasoning: 2 teaspoons for the sauce (or substitute a favorite blend).
• Fresh garlic: 4 cloves, minced.
• Olive oil: About 1½ tablespoons, divided for sautéing and drizzling.
• Salt and pepper: To taste.
• Mozzarella and parmesan: 3 cups shredded mozzarella (divided) and 1 cup grated parmesan (divided).
• Panko breadcrumbs: 1 cup for a crisp topping (regular or gluten-free).
• Fresh parsley and extra parmesan: For garnish.

How to Make Cheesy Zucchini and Squash Casserole

1. Preheat and prep. Preheat the oven to 375°F. Grease a 9×13-inch baking dish with a bit of butter. Slice or spiralize the zucchini and yellow squash, place them in a colander, sprinkle with salt, and allow them to drain.
2. Make the cream sauce. Melt the butter in a saucepan over medium heat. Whisk in the flour and cook for about 2 minutes. Gradually whisk in the milk and Italian seasoning until smooth. Simmer, whisking frequently, for 8–10 minutes until the sauce thickens.
3. Dry and season the squash. Pat the drained squash and zucchini dry with paper towels, then toss in a large bowl with minced garlic, ½ tablespoon olive oil, and a pinch of salt and pepper.
4. Sauté the vegetables. Heat the remaining 1 tablespoon olive oil in a large skillet over medium-high heat. Add the squash mixture and cook for about 3 minutes, stirring, until it just begins to soften. Drain any excess liquid and set aside.
5. Layer the casserole. Spread ¾ cup of the cream sauce over the bottom of the prepared baking dish. Arrange half of the sautéed squash over the sauce, then sprinkle with 1 cup mozzarella and ⅓ cup parmesan. Repeat with the remaining squash and sauce, then top with the remaining cheeses.
6. Add the topping and bake. Sprinkle panko crumbs evenly over the top and drizzle lightly with olive oil. Bake for 30–35 minutes, until the top is golden and bubbly. Let cool for 10 minutes, then garnish with chopped parsley and extra parmesan before serving.

Tips for Success

• Avoid overcooking: Sauté the squash only until it starts to soften; it will continue to cook in the oven. Overcooking beforehand can make the casserole watery or mushy.
• Season carefully: Taste the sauce and seasoned vegetables before assembling so you can adjust salt and pepper. Balancing flavors in each component gives the best final result.
• Swap freely: If you don’t have both zucchini and yellow squash, use whichever you have on hand—this recipe works well with just one variety.

Variation Ideas!

• Cajun twist: Swap the Italian seasoning for a Cajun blend, reducing any added salt since many blends are salted. Use less if you prefer milder heat.
• Different vegetables: Try the same sauce-and-cheese method with lightly steamed broccoli and cauliflower for a different take.
• Make it a main: Add cooked Italian sausage, shredded chicken, or diced ham between layers for a heartier main-dish casserole.

What Goes with Zucchini and Squash Casserole?

• Fish or seafood: A simply seasoned roasted salmon pairs well with the creamy vegetable casserole.
• Chicken: Pan-seared or roasted chicken thighs make an easy, satisfying entree alongside this side dish.
• Light desserts: Finish the meal with a light, classic dessert to balance the richness of the casserole.

How to Store and Reheat Leftovers

• Refrigerate: Store leftovers in an airtight container in the refrigerator for up to 4 days.
• Freeze: Transfer cooled portions to freezer-safe containers or bags, removing as much air as possible before sealing.
• Reheat: Reheat portions in an ovenproof dish at 350°F until heated through. Frozen portions will take longer—heat until fully warmed before serving.