Zucchini Casserole

A comforting, cheesy zucchini casserole that transforms fresh zucchini into a creamy, flavorful side dish or light main course. This easy recipe combines tender zucchini, savory onions, melted cheese, and a crispy topping for the perfect balance of texture and flavor. It’s an excellent way to use up an abundance of zucchini and makes a wonderful addition to family dinners, holiday meals, or potluck gatherings.

Ingredients For the Casserole

4 medium zucchini, sliced into thin rounds
1 medium onion, finely chopped
2 tablespoons butter
2 large eggs, lightly beaten
1 cup sour cream
1 cup shredded cheddar cheese
½ cup grated Parmesan cheese
1 teaspoon garlic powder
½ teaspoon dried Italian seasoning
½ teaspoon salt
¼ teaspoon black pepper

For the Topping

1 cup crushed buttery crackers or breadcrumbs
2 tablespoons melted butter
¼ cup grated Parmesan cheese

Instructions

Step 1: Prepare the Oven and Baking Dish

Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish or a similar-sized casserole dish and set aside.

Step 2: Cook the Vegetables

Melt 2 tablespoons of butter in a large skillet over medium heat. Add the chopped onion and cook for 3–4 minutes until softened. Add the sliced zucchini and cook for another 5–7 minutes, stirring occasionally, until the zucchini begins to soften. Remove from the heat and allow the mixture to cool slightly.

Step 3: Make the Creamy Mixture

In a large mixing bowl, whisk together the eggs, sour cream, cheddar cheese, Parmesan cheese, garlic powder, Italian seasoning, salt, and black pepper. Stir until everything is well combined.

Step 4: Combine the Ingredients

Add the cooked zucchini and onion mixture to the bowl with the creamy cheese mixture. Gently fold everything together until the vegetables are evenly coated.

Step 5: Prepare the Topping

In a small bowl, combine the crushed crackers or breadcrumbs with the melted butter and Parmesan cheese. Mix until the crumbs are evenly moistened.

Step 6: Assemble the Casserole

Spread the zucchini mixture evenly into the prepared baking dish. Sprinkle the crumb topping evenly across the surface, covering the casserole completely.

Step 7: Bake

Bake for 25–30 minutes, or until the casserole is bubbly around the edges and the topping is golden brown. If needed, broil for 1–2 minutes at the end to achieve extra crispness on top.

Step 8: Rest and Serve

Remove the casserole from the oven and let it rest for 5–10 minutes before serving. This helps the casserole set and makes it easier to portion.

Tips and Notes

For a richer flavor, substitute part of the cheddar cheese with mozzarella, Monterey Jack, or Gruyère.
If your zucchini contains a lot of moisture, lightly salt the slices and let them sit for 15 minutes before cooking. Pat dry with paper towels to reduce excess liquid.
Add cooked bacon, diced ham, or shredded chicken to turn this side dish into a hearty main course.
Fresh herbs such as parsley, chives, or basil can be added for extra freshness.
Leftovers can be stored in an airtight container in the refrigerator for up to 3 days and reheated in the oven or microwave.

Q&A

Can I make this casserole ahead of time?
Yes. Assemble the casserole up to one day in advance, cover, and refrigerate. Add the topping just before baking for the best texture.

Can I freeze zucchini casserole?
Yes, although the texture may soften slightly after thawing. Freeze after baking and cooling completely for up to 2 months.

Can I use yellow squash instead of zucchini?
Absolutely. Yellow squash works well and can be substituted entirely or combined with zucchini.

Servings & Nutrition

Servings: 8

Approximate Nutrition Per Serving:

Calories: 230
Protein: 10g
Carbohydrates: 10g
Fat: 17g
Saturated Fat: 9g
Fiber: 2g
Sugar: 4g
Sodium: 420mg

This zucchini casserole is creamy, cheesy, and wonderfully satisfying, making it a reliable recipe for both weeknight meals and special gatherings. The combination of tender vegetables and crunchy topping creates a delicious dish that even picky eaters often enjoy.