Zucchini Squash & Corn Casserole

Why You’ll Love This Recipe

I love this casserole because it’s simple, flexible, and full of flavor. It’s creamy and cheesy without being too heavy, and the combination of zucchini, squash, and corn gives it a wonderful mix of textures and sweetness. It’s easy to prep ahead, works for any meal of the day, and can be served warm or at room temperature — making it perfect for gatherings or casual weeknight dinners.

ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

• 2 medium zucchinis, sliced

• 2 medium yellow squash, sliced

• 1 cup corn kernels (fresh or frozen)

• 1/2 cup sour cream

• 1/2 cup mayonnaise

• 1 cup shredded cheddar cheese

• 1/4 cup grated Parmesan cheese

• 1/4 cup breadcrumbs (optional for topping)

• 1 tablespoon olive oil

• 1/2 teaspoon garlic powder

• 1/2 teaspoon onion powder

• Salt and pepper to taste

• Fresh parsley, chopped for garnish

directions

1. I start by preheating the oven to 375°F (190°C) and greasing a 9×9-inch baking dish with olive oil or cooking spray.

2. In a large skillet, I heat the olive oil over medium heat, then add the sliced zucchini and squash. I sauté them for 4–5 minutes until they begin to soften.

3. I add the corn to the skillet and cook for another 2–3 minutes, stirring occasionally, then remove the pan from the heat.

4. In a separate bowl, I whisk together the sour cream, mayonnaise, cheddar cheese, Parmesan, garlic powder, onion powder, salt, and pepper until smooth and well combined.

5. I gently fold the cooked vegetables into the cheese mixture until everything is evenly coated.

6. I transfer the mixture to the prepared baking dish and spread it out evenly.

7. If I want a crunchy topping, I sprinkle breadcrumbs over the surface before baking.

8. I bake the casserole for 25–30 minutes, until it’s golden brown and bubbling around the edges.

9. After letting it cool slightly, I garnish it with chopped fresh parsley and serve it warm.

Servings and timing

This recipe makes 6 servings and takes about 45 minutes total — 15 minutes to prep and 30 minutes to bake. It’s ideal as a side dish or light vegetarian main, especially when I’m looking for something satisfying without a lot of fuss.

Variations

• I sometimes add diced red bell pepper or chopped spinach for more color and flavor.

• For extra richness, I swap cheddar for a cheese blend like Gruyère or Monterey Jack.

• To make it gluten-free, I skip the breadcrumbs or use gluten-free panko.

• I add a pinch of cayenne or red pepper flakes for a little kick.

storage/reheating

I store leftovers in an airtight container in the fridge for up to 3 days. To reheat, I use the oven at 350°F for 10–15 minutes or microwave individual portions. It reheats well and tastes just as good the next day.

FAQs

Can I use canned corn instead of fresh or frozen?

Yes, I drain canned corn well before adding it. It works just fine and still brings that sweet bite to the dish.

Do I need to peel the zucchini and squash?

No, I leave the skins on. They soften during cooking and add a nice texture and color to the casserole.

Can I make this casserole ahead of time?

Absolutely. I assemble the casserole, cover it, and store it in the fridge up to a day ahead. Then I bake it when I’m ready to serve.

Is it okay to skip the mayonnaise?

Yes, I substitute with extra sour cream or Greek yogurt if I prefer a lighter version without mayo. The texture stays creamy and satisfying.

Can I freeze this casserole?

I don’t recommend freezing it, as the texture of the squash and dairy-based filling can become watery when thawed. It’s best enjoyed fresh or from the fridge within a few days.

Conclusion

Zucchini Squash & Corn Casserole is a delicious way to showcase fresh vegetables in a creamy, cheesy bake that’s easy enough for weeknights but elegant enough for gatherings. I love how versatile and comforting it is — the kind of dish that’s always welcome at my table, whether as a main or a side. It’s warm, satisfying, and packed with flavor in every bite.