This zucchini casserole is amazing! Layers of zucchini, marinara sauce, and mozzarella combine to create a pizza-like experience.
Even the leftovers are excellent, so I often double this recipe and make two casseroles.
I enjoy zucchini in many recipes, including grilled zucchini, zucchini lasagna, zucchini noodles, and zucchini chips.
This zucchini casserole is especially good. It's incredibly flavorful and easy to make. It's one of my favorite ways to enjoy this vegetable. Happily, my entire family agrees, including the youngest one. This casserole is a great way to get picky eaters to eat zucchini.
Jump to:
Ingredients
You'll only need a few simple ingredients to make this zucchini casserole. The exact measurements are included in the recipe card below. Here's an overview of what you'll need:
- Olive oil spray: This is my favorite oil. It's so flavorful!
- Fresh zucchini: Try to pick firm zucchini with smooth, dark green skin.
- Kosher salt and black pepper: I use Diamond Crystal Kosher Salt and freshly ground black pepper.
- Marinara sauce: It's best to use a sugar-free sauce such as Rao's Marinara Sauce.
- Spices: I use dried oregano and garlic powder.
- Cheeses: I use shredded mozzarella and grated parmesan in this recipe.
Variations
- You can use different cheeses, including provolone and mild gouda. I especially like provolone in this recipe.
- Make it spicy by adding a generous pinch of cayenne pepper or ½ teaspoon of red pepper flakes.
- Sometimes, I replace the marinara sauce with the same amount (1 cup) of sour cream. The rest of the recipe remains the same. It creates a different flavor profile - milder and creamier.
Zucchini Casserole Instructions
The detailed instructions for making this recipe are listed in the recipe card below. Here's an overview of the steps:
Slice the unpeeled zucchini into ½-inch thick slices. Sprinkle the slices with salt. Place them in a colander and allow them to drain at room temperature for 30 minutes. This step helps prevent a watery casserole.
Mix the drained zucchini slices with marinara sauce, spices, and shredded cheese.
Transfer the mixture to a greased baking dish and sprinkle the top with more cheese.
Bake the casserole until browned and bubbly, for about 30 minutes, in a 400°F oven.
Expert Tips
- Salting and draining the zucchini is an important step, which I also take when making zucchini chips and roasted zucchini. It helps eliminate excess water and keeps the casserole from becoming watery or soggy. Zucchini has a high water content - nearly 95%. We don't want that water seeping into the casserole.
- I don't rinse the zucchini after salting and draining it, so there's no need to add salt when seasoning the casserole.
Recipe FAQs
You might. The marinara sauce and cheese do an excellent job of masking the zucchini's flavor. I have a picky child at home, and this recipe is one of the only ways to get her to eat zucchini.
Having said that, another tasty casserole with similar flavors and no zucchini is this keto pizza casserole.
Yes. Pick firm squashes and salt them to draw out excess liquids.
Yes. Provolone is an excellent substitute that I often use. You can also use one of those bags of shredded cheese labeled as "Italian mix."
I don't recommend using frozen zucchini in this recipe. You should use fresh zucchini for the best flavor and texture.
Serving Suggestions
This zucchini casserole makes an excellent side dish to almost any main course you can think of. I often serve it with one of the following:
Storing Leftovers
You can keep the leftovers in the fridge, in an airtight container, for 3-4 days. Reheat them gently in the microwave at 50% power. They are also surprisingly good when eaten cold! I don't recommend freezing the leftovers.
More Zucchini Recipes
Foodie Newsletter
I send out a weekly newsletter with a recipe and tips. Want these recipes in your inbox? Subscribe today! You can unsubscribe at any time.
Recipe Card
Cheesy Zucchini Casserole
Ingredients
- Olive oil spray
- 6 medium zucchini - (2 pounds)
- 1 teaspoon Diamond Crystal kosher salt - or ½ teaspoon of any other salt
- 1 cup marinara sauce
- ¼ teaspoon black pepper
- 1 teaspoon dried oregano
- 1 teaspoon garlic powder
- 1 ½ cups mozzarella - part-skim, shredded, divided (6 ounces)
- 2 tablespoons parmesan - grated
Instructions
- Preheat the oven to 400°F. Spray a 2-quart baking dish with olive oil spray.
- Slice the unpeeled zucchini into ½-inch thick slices. Sprinkle the slices with salt. Place them in a colander and allow them to drain at room temperature for 30 minutes. This step helps prevent a watery casserole.
- Transfer the drained zucchini to a large bowl. Add the marinara sauce, black pepper, dried oregano, garlic powder, and 1 cup of mozzarella. Mix to combine.
- Transfer the mixture to the prepared baking dish. Sprinkle it with the remaining mozzarella and with the parmesan. Bake uncovered until the cheese is bubbly and browned, about 30 minutes.
- Let the casserole rest for 10 minutes before serving it. Like all casseroles, it tastes best when warm or at room temperature.
Video
Notes
- This is an easy recipe, but one step you should not skip is salting and draining the zucchini. It helps eliminate excess water and keeps the casserole from becoming soggy.
- I don't rinse the zucchini after salting and draining it, so there's no need to add salt when seasoning the casserole.
- Sometimes, I replace the marinara sauce with the same amount (1 cup) of sour cream. The rest of the recipe remains exactly the same. It creates a different flavor profile - milder and creamier.Â
- You can keep the leftovers in the fridge, in an airtight container, for 3-4 days. Reheat them gently in the microwave at 50% power. They are also surprisingly good when eaten cold! I don't recommend freezing the leftovers.Â
Nutrition per Serving
Disclaimers
Cup measurements refer to the standard American cup, which is 240 milliliters. Most of my recipes are low-carb (or keto) and gluten-free, but some are not. Please verify that a recipe fits your needs before using it. Recommended and linked products are not guaranteed to be gluten-free. Nutrition info is approximate, and the carb count excludes non-nutritive sweeteners. Nutrition info may contain errors, so please verify it independently. Recipes may contain errors, so please use your common sense when following them. Please read these Terms of Use carefully before using any of my recipes.
Vered DeLeeuw, LL.M., CNC, has been following a low-carb real-food diet and blogging about it since 2011. She's a Certified Nutrition Coach (NASM-CNC), has taken courses at the Harvard School of Public Health, and has earned a Nutrition and Healthy Living Certificate from Cornell University. Her work has appeared in several major media outlets, including Healthline, HuffPost, Today, Women's Health, Shape, and Country Living. 
MonaLisa
I'd like to assemble this today and cook tomorrow. Is that possible? Thank you!
Vered DeLeeuw
Yes. Tomorrow, there will likely be liquid on the bottom of the casserole. Tilt it carefully to drain. Remove the casserole dish from the fridge 30 minutes before placing it in the oven to avoid placing a cold ceramic or glass dish in a hot oven.
Cheryll
Do you wash the salt off before adding the marinara?
Vered DeLeeuw
I don't. But I use Diamond Crystal Kosher salt, which is relatively low in sodium. If you use any other salt, it's not a bad idea to rinse the zucchini slices and pat dry them before adding the marinara.