This old fashioned recipe for Zucchini Casserole is the perfect mix of fresh zucchini, dried herbs, and cheese with a biscuit coating.
Old Fashioned Zucchini Casserole is the perfect way to give the humble zucchini LOTS of flavor!
It starts with plenty of zucchini, which gets paired with onions, dried oregano, and melty cheddar in this hearty veggie side dish.
It also employs a shortcut ingredient: Bisquick! The biscuit mix helps hold everything together while lending a biscuit-like coating around the zucchini.
This casserole is truly a delightful side dish for the summer months (and into fall and winter, too!).
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- Take care to cook this casserole all the way through. It has eggs in it, which can make it runny if undercooked.
- You’ll need 6–7 cups of chopped zucchini. That’s roughly 4 small zucchini, or 2–3 medium. Thankfully, this recipe is forgiving if you use slightly more/less, so don’t sweat it if it’s a little over or under!
- This casserole is best served the day it is made. If you have leftovers, you can reheat them in the oven.
- Zucchini and cheddar cheese are the stars of this casserole. You can use whatever variety of shredded cheese that you like.
- Onion and dried oregano complement the zucchini nicely.
- Eggs and Bisquick hold it all together!
- You’ll also need oil and salt.
How to make old fashioned zucchini casserole
Start by chopping the zucchini into half-inch pieces.
You’ll need 6–7 cups total. It’ll be fine if you’re a little over or under.
Next, place the zucchini, onion, Bisquick, ¾ cup cheddar, salt, and oregano in a large bowl.
You’ll save the remaining ¾ cup of cheese for the top.
Then, whisk together the eggs and oil.
Pour the egg mixture over the zucchini mixture, and toss gently to combine.
Pour the mixture into a greased 8×8 inch pan, and top with the remaining ¾ cup cheese.
Bake the zucchini casserole for 45–50 minutes, or until the casserole no longer jiggles in the middle when you jostle the pan back and forth.
Let the casserole cool for 10 minutes before serving.
Make it ahead
This old fashioned Zucchini Casserole is best served right after it’s baked. And, I recommend assembling it and then baking it right away.
That said, you can chop the zucchini and onion ahead of time. Cover and store in the refrigerator for up to 24 hours.
Then, when it’s time to make the casserole, you just need to stir everything together and bake it.
Here are a few ideas for substitutions and variations:
- Substitute yellow squash for the zucchini (or use a mix of the two)
- Use dried basil instead of dried oregano
- Use fresh oregano or fresh basil instead of dried oregano (triple the amount)
- Use colby jack or your favorite type of shredded cheese in place of the cheddar
Can zucchini casserole be frozen?
To freeze, bake the casserole as directed and let cool completely. Wrap the pan in plastic wrap and then aluminum foil, and freeze for up to 2 months.
Defrost in the refrigerator for 24 hours, then remove the plastic wrap and foil, and bake at 350°F until warm.
What to serve with zucchini casserole
I love serving this casserole on a warm summer evening with grilled chicken or burgers. It’s also really nice with a roast chicken.
Here are few more main dishes to serve it with:
More zucchini recipes
Have you tried this recipe? Please leave a ⭐️⭐️⭐️⭐️⭐️ rating and/or comment below!
Old Fashioned Zucchini Casserole
- 6–7 cups chopped zucchini cut into ½ inch cubes (about 4 small zucchini or 2–3 medium)
- 1 small onion chopped
- 1¼ cups Bisquick
- 1½ cups shredded cheddar divided
- 1 teaspoon salt
- 1 teaspoon oregano
- 3 eggs
- ½ cup vegetable oil
- Grease a 9×9 inch dish with cooking spray. Preheat oven to 350°F.
- Place the zucchini, onion, Bisquick, ¾ cup cheddar, salt, and oregano in a large bowl.
- In another bowl, whisk together 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 1 cup cheddar.
- Bake for 45–50 minutes, or until the casserole no longer jiggles in the middle when you jostle it back and forth. Serve immediately.