This zucchini casserole is a cheesy, flavorful dish featuring tender zucchini layered with marinara sauce and melted mozzarella. It has all the comforting flavors of pizza in an easy vegetable casserole.

I enjoy zucchini in many recipes, including grilled zucchini, zucchini lasagna, and zucchini noodles. But this cheesy, flavorful casserole is a favorite, and even picky eaters in my family enjoy it. In fact, this recipe is a great way to get picky eaters to eat zucchini! The leftovers are excellent, too, so I often double the recipe.
Ingredients

See the recipe card for exact measurements. Here are my comments on some of the ingredients.
- Fresh zucchini: Try to pick firm zucchini with smooth, dark green skin.
- Marinara sauce: It's best to use a sugar-free sauce such as Rao's Marinara Sauce.
- To season: Dried oregano and garlic powder.
- Cheeses: I use shredded mozzarella and grated Parmesan. Provolone is a good substitute for the mozzarella, although it has a slightly stronger flavor.
Sour Cream Variation
Sometimes, I replace the marinara sauce with the same amount (1 cup) of sour cream and the mozzarella with sharp cheddar, omitting the Parmesan. It creates a completely different flavor profile that is just as good. The first image below shows the variation ingredients in a bowl ready for mixing, and the second photo shows the baked casserole.


Instructions
The detailed instructions and step-by-step photos are included in the recipe card. Here's a quick overview.
Salt and drain the zucchini slices, then mix them with marinara sauce, seasonings, and shredded cheese.

Transfer the mixture to a greased baking dish and sprinkle the top with more cheese.

Bake the casserole at 400°F until browned and bubbly, for about 30 minutes.

A friend gave me a bunch of zucchini and I had no idea what I could make besides zucchini bread. I love this recipe. It is simple and elegant at the same time. You made my dinner!
Edilsa
Read more comments
Tip: Salting the Zucchini is a Must
Salting and blotting the zucchini dry are important steps, which I also take when making zucchini chips and roasted zucchini. These extra steps help eliminate excess water, keeping the casserole from becoming watery or soggy.
The image below clearly shows water droplets on the zucchini's surface after it was salted. This is exactly the excess liquid we want to remove. The salt did its job and drew it out.

Recipe FAQs
I don't recommend using frozen zucchini in this recipe. Please use fresh zucchini for the best flavor and texture.
I don't rinse the zucchini after salting and draining it, so there's no need to add salt when seasoning the casserole.
Absolutely. Cooked ground beef, Italian sausage, or shredded chicken are good options. Make sure the meat is fully cooked before adding it to the casserole.
Yes. You can assemble the casserole a few hours ahead, cover it, and refrigerate it. Bake it when you're ready to serve. Remember to remove the baking dish to the counter 30 minutes before placing it in a hot oven.
Serving Suggestions
I like to pair this casserole with a main course I can bake in the same 400°F oven, such as:
- Buffalo chicken drumsticks
- Baked drumsticks
- Baked boneless chicken thighs
- Baked pork chops
- Baked shrimp
- Baked meatballs, as shown in the image below

Storing and Using the Leftovers
Keep the leftovers in an airtight container (like the one shown below) in the fridge for 3-4 days. I don't recommend freezing the leftovers.

Reheat them in the microwave or in a 350°F oven (remove the pan from the fridge 30 minutes before placing it in the oven).
The leftovers are also surprisingly good when eaten cold! The photo below shows an easy lunch of the leftovers served with a fresh tomato salad. They are also good with creamy cucumber salad or Caesar salad.

Recipe Card

Zucchini Casserole
Video
Ingredients
- Olive oil spray
- 6 medium zucchini - 2 pounds, unpeeled
- 1 teaspoon Diamond Crystal kosher salt - or ½ teaspoon of any other salt, including Morton kosher 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.Olive oil spray
- Slice the zucchini into ½-inch thick slices. Place the slices on paper towels and sprinkle them with the salt. Allow them to sit at room temperature for 30 minutes, then blot dry.6 medium zucchini, 1 teaspoon Diamond Crystal kosher salt
- Transfer the zucchini slices to a large bowl. Add the marinara sauce, black pepper, dried oregano, garlic powder, and 1 cup of mozzarella. Mix to combine.1 cup marinara sauce, ¼ teaspoon black pepper, 1 teaspoon dried oregano, 1 teaspoon garlic powder, 1 ½ cups mozzarella
- Transfer the mixture to the prepared baking dish. Sprinkle it with the remaining mozzarella and the Parmesan. Bake uncovered until the cheese is bubbly and browned, about 30 minutes.2 tablespoons Parmesan
- Let the casserole rest for 10 minutes before serving it. Like all casseroles, it tastes best when warm, not piping hot.
Notes
- Salting the zucchini helps eliminate excess water and keeps the casserole from becoming soggy.
- I don't rinse the zucchini after salting and blotting it dry, so there's no need to add salt when seasoning the casserole.
- You can assemble the casserole a few hours ahead, cover it, and refrigerate it. Bake it when you're ready to serve. Remember to remove the baking dish to the counter 30 minutes before placing it in a hot oven.
- You can add cooked ground beef, Italian sausage, or shredded chicken to the casserole. Make sure the meat is fully cooked before adding it to the casserole.
- Keep the leftovers in an airtight container in the fridge for 3-4 days. Reheat them gently in the microwave at 50% power or in a 350°F oven (remove the baking dish to the counter 30 minutes before placing it in a hot oven). They are also good when eaten cold! I don't recommend freezing the leftovers.
Nutrition per Serving
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Disclaimers
Most recipes are low-carb and gluten-free, but some are not. Recommended products are not guaranteed to be gluten-free. Nutrition info is approximate - please verify it. The carb count excludes non-nutritive sweeteners. Please read these Terms of Use before using any of my recipes.










Jay says
Yum, I usually cook the traditional casserole.
Figure I would try this one... Glad I did.
I did add onions, peppers, leftover cooked Italian sausage and pepperoni and extra cheese .
I think you could add whatever pizza topping you like best.
Vered DeLeeuw says
Thanks for the review and for sharing your delicious tweaks, Jay!
Kandi says
Delicious!
Vered DeLeeuw says
So glad you enjoyed it! Many thanks for the review.
Bridget M Misenhimer says
Can you make this recipe in advance before cooking? Or will the zucchini absorb the sauce? Thank you!
Vered DeLeeuw says
Hi Bridget,
You can assemble this casserole ahead of time, but it's not ideal, as it could become soggy. If you must, I recommend firmly patting the zucchini slices dry with paper towels after salting and before mixing them with the sauce to remove as much water as possible.
Once the zucchini is thoroughly drained and patted dry, toss it with the marinara sauce, spices, and the first portion of mozzarella. Transfer the mixture to your greased baking dish and top with the remaining cheese. Cover the dish tightly with plastic wrap and store in the fridge for no longer than 24 hours.
When you are ready to bake, take the casserole out of the fridge and let it sit on the counter for about 30 minutes to take the chill off while your oven preheats. Remove the plastic wrap and bake uncovered. Because the ingredients will start out colder than a freshly made casserole, you may need to add 5 to 10 minutes to the baking time.
Edilsa says
A friend gave me a bunch of zucchini and I had no idea what I could make besides zucchini bread.
I love this recipe. It is simple and elegant at the same time.
You made my dinner!
Vered DeLeeuw says
Oh, Edilsa, I'm so happy to hear that! Thank you so much for taking the time to write this review - I appreciate it.
JoAnn says
"Mmmm, tastes like pizza!", said my husband. Excellent recipe. I used (Cabot) Muenster cheese. Salad (& a small piece of bread-sorry) on the side. Thanks for another great recipe.
Vered DeLeeuw says
You're very welcome, JoAnn! Thank you for trusting my recipes. Bread is fine (and delicious) for those who can handle it!