Classic Old-Fashioned Zucchini Casserole Recipe for Family Meals

This old-fashioned Zucchini Casserole combines fresh zucchini, dried herbs, and melted cheese with a biscuit-like coating for a flavorful, comforting side dish.

Old Fashioned Zucchini Casserole is an easy, satisfying way to turn abundant summer zucchini into a cheesy, savory casserole. The recipe pairs chopped zucchini with onion, dried oregano, and cheddar, and uses Bisquick to create a biscuit-like binder and topping.

This casserole makes a great summer side dish and is forgiving about exact quantities—perfect if you have a surplus of zucchini. It reheats well and can be frozen after baking for later use.

Top tips

• Make sure to bake the casserole completely. The eggs need time to set so the center doesn’t remain runny.
• You’ll need about 6–7 cups chopped zucchini—roughly 4 small or 2–3 medium zucchini. A little more or less will be fine.
• Serve this casserole the day it’s baked for best texture. Leftovers reheat nicely in the oven or microwave.

Ingredients

See the recipe card below for exact amounts and the full method.

How to make old fashioned zucchini casserole

Begin by chopping zucchini into ½-inch cubes. You’ll want 6–7 cups total.

In a large bowl, combine the chopped zucchini, chopped onion, Bisquick, ¾ cup of the shredded cheddar, salt, and dried oregano.

Whisk the eggs and vegetable oil together in a separate bowl, then pour the mixture over the zucchini mixture and toss gently to coat.

Transfer the mixture to a greased 8×8 or 9×9-inch baking dish and sprinkle the remaining cheese evenly over the top.

Bake at 350°F for 45–50 minutes, or until the casserole no longer jiggles in the center when you gently shake the pan. Let cool for 10 minutes before serving.

Make ahead & Freezing instructions

This casserole is best served fresh from the oven, so plan to bake it shortly after assembling. You can, however, chop the zucchini and onion up to 24 hours ahead and store them covered in the refrigerator. When ready, combine ingredients and bake as directed.

To freeze: bake the casserole, cool completely, wrap tightly in plastic wrap and foil, and freeze for up to 2 months. Thaw in the refrigerator for 24 hours, then reheat in a 350°F oven until warmed through.

📖 Recipe

Old Fashioned Zucchini Casserole

Chopped zucchini and onion baked with Bisquick and cheddar for a cheesy, biscuit-like casserole.

Prep Time 10 mins

Cook Time 45 mins

Total Time 55 mins

Course Side Dish

Cuisine American

Servings 8 servings

Calories 335 kcal

Ingredients

• 6–7 cups chopped zucchini (cut into ½-inch cubes; about 4 small or 2–3 medium)
• 1 small onion, chopped
• 1¼ cups Bisquick
• 1½ cups shredded cheddar, divided
• 1 teaspoon salt
• 1 teaspoon dried oregano
• 3 eggs
• ½ cup vegetable oil

Instructions

• Grease a 9×9-inch dish with cooking spray and preheat the oven to 350°F.
• In a large bowl, combine the zucchini, onion, Bisquick, ¾ cup cheddar, salt, and oregano.
• In a separate bowl, whisk the eggs and vegetable oil. Pour over the zucchini mixture and stir to combine.
• Pour the mixture into the greased dish and top with the remaining cheddar.
• Bake 45–50 minutes, until the center is set and the casserole no longer jiggles. Let cool 10 minutes and serve.

Notes

Reheat: Warm leftovers in the microwave or oven.

Substitute yellow squash for zucchini or add fresh herbs (use about three times the amount when substituting fresh for dried).

Make ahead: Chop zucchini and onion up to 24 hours in advance and refrigerate. Stir together and bake when ready.

Freeze: Bake, cool completely, wrap tightly, and freeze up to 2 months. Thaw in the refrigerator for 24 hours and reheat in the oven.

Nutrition

Calories: 335 kcalCarbohydrates: 17 gProtein: 10 gFat: 26 g

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