Cheesy Zucchini Casserole is packed with fresh zucchini, three kinds of cheeses, and seasoning for an indulgent fall-themed side dish or vegetarian main dish. This is a great Keto meal that is also simple, hearty, and delicious for the whole family to enjoy!

Casserole dishes, especially the meat-free ones, don’t have to be bland and forgettable. In fact, the Best Stuffed Mushrooms, buttery Easy Instant Pot Polenta, and Slow Cooker Scalloped Potatoes are sure to steal the show at the dinner table!

This Cheesy Baked Zucchini Casserole is always a huge hit when I bring it to any party, potluck, or weekend get-together. It’s impossible to say no to this creamy and ultra-cheesy vegetarian dish! You will love this recipe!

It is loaded with cheddar cheese, mozzarella cheese, and Mexican cheese, then baked till golden brown. The melted butter combined with rich creamy cheeses sauce makes this dish irresistible. Even kids love it! It is a great way to get them to eat vegetables and actually enjoy the meal.

With just a few substitutions, you can turn this into a low-carb and keto-friendly recipe. It’s so easy to make too. Once all the ingredients are prepped, all that’s left is to mix it all up and bake! Say hello to your newest favorite casserole!

Recipe Ingredients:

This is easy comfort food that requires a few, simple ingredients. You will need the following:

Zucchini: I go with fresh zucchini, around 6 medium pieces. Also, feel free to mix in some yellow squash as well. For this recipe, I recommend buying the thickest zucchini. That way, you can so you get bigger round slices to layer into the casserole dish.
Salt: for salting the veggies and to season the dish
White rice: cooked as you like it
Greek yogurt and sour cream: the creamy base of the dish
Lemon juice: brightens up the flavors and cuts through the richness of the dish
Eggs: around 4 large pieces for structure
Seasonings: smoked paprika, onion powder, black pepper, and finely minced garlic
Baking powder: to lighten the texture of the dish
Cheese: shred mozzarella, Mexican cheese, and cheddar
Green onions: for adding into the dish and garnish

How to make Baked Cheesy Zucchini Casserole?

Preheat oven: First, preheat the oven to 400 degrees F.
Get the zucchini ready. Grate, then salt lightly. Let stand for at least 10 mins, stirring a couple of times. Remember that these veggies contain a lot of water. Therefore, squeeze as much water as you can and use paper towels to absorb as much water as you can.
Prepare the sour cream mix. Then, in a large bowl, combine the lemon juice, sour cream, and baking powder. Let stand for around 10 minutes.
Make the veggie mixture. Stir the eggs into the drained veggies along with the sour cream mix. Add the rice, a cup of cheddar, and a cup of Mexican cheese. Stir in the seasonings and green onions.
Assemble. Next, pour into a buttered baking dish, then top with a half cup of yogurt. Bake without cover at 400F for around 20 mins.
Top with more cheese. Sprinkle the rest of the cheese on top and continue baking until bubbly and golden.
Serve. Cool for at least 10 mins before cutting and serving. To serve, scoop a little sour cream on top, then sprinkle green onions plus chopped tomatoes.

Variations and substitutions

Cheese: Feel free to use your favorite cheeses or a combination of different cheeses. Great alternatives would be Parmesan cheese, gruyere cheese, Monterey Jack, spicy pepper jack, provolone, fontina, or even feta.
Seasonings: Use whatever you like. Ranch seasoning, Italian seasoning, garlic powder, chili powder, etc.
Other veggies: Swap the fresh zucchini with yellow squash, broccoli, summer squash, cauliflower, steamed green beans, peas. etc. It works really well with butternut squash for a more fall/winter-themed dish.
Make it a one-dish meal with meat. To turn it into a full meal, you can add meat like shredded rotisserie chicken, ground beef, bacon, sausages, ham, or pork. Make sure to pre-cook before adding on top of the vegetable layer.
Make it spicier. Mix cayenne pepper to taste into the dish or top with bits of jalapeno.
Healthier. For a lighter version, try subbing with low-fat or vegan cheese, Greek yogurt instead of sour cream, or try halving the amount of cheese. Use brown rice, buckwheat, or quinoa for more fiber.
Low-carb. Sub out the white rice with riced cauliflower or riced veggie mix.

How thick should the zucchini slices be?

I like mine around ¼ inch thick or shredded. It ensures that the vegetable becomes tender and fully cooked without disintegrating into the cheese and cream.

Also, cutting them thicker means that the zucchini won’t be mushy when baked, and hold their texture well. Remember, that the thicker the slices are, the better they cook with a perfect texture but still al dente. Just ideal when combined with melted cheese.

How to keep your Squash Casserole from being watery?

Zucchini is naturally very watery. That’s why you shouldn’t skip salting it, letting it stand, then squeezing the vegetables for this recipe. If you do, you’re risking soggy and mushy results.

What the salt does is draw out all that excess moisture and bitterness through a process called osmosis. In addition, it also helps the veggies retain their shape. Once the dish is ready to cut, you get firm and compact slices instead of layers that keep sliding around.

The same applies to the shredded zucchini, when you add the salt, let it stand a bit, and after that squeeze all the extra moisture.

Can I add chicken?

Yes! As stated above, you may easily turn this into a full meal. Simply add pre-cooked shredded chicken or leftover chicken.

In addition, this recipe works great with ground beef, pork, or turkey.

What to serve with zucchini casserole?

This cheesy side dish goes well with pretty much any main entrée. I love serving it alongside:

Storing instructions:

To refrigerate, first, make sure any leftovers are completely cool. Then, refrigerate leftovers using a sealed container or an airtight container for up to 3 days.

I also like slicing it into separate portions and storing them individually. That way, people can just get a ready-to-heat serving. To heat, microwave for a few minutes ‘til hot or bake at 350F until heated through.

More delicious casserole recipes:

Cooking Tips:

For cleaner slices, let cool for 10-20 minutes before slicing.
Don’t skip salting and draining the veggies.
Alternatively, feel free to slice the veggies into half-moons or shred them in a processor.
Also, you can swap the sour cream with heavy cream or cream cheese.
For a crunchier top, add some bread crumbs, Panko breadcrumbs, bacon bits, French fried onions, etc.
Use lots of cheese. To make it even creamier and cheesier, feel free to use extra cheese.