Cheesy baked zucchini side dish

I didn't grow up thinking of zucchini as exciting. Honestly, I used to think it was just something you threw into a stir-fry when you had nothing else in the fridge. That all changed one summer evening when I had way too many zucchini from the farmers market and zero motivation to make anything complicated.

Jump to:

• Why You Will Like This Recipe
• What You Need for This Cheesy Zucchini Casserole
• How to Make This Cheesy Zucchini Casserole Step by Step
• Storage and Reheating
• Tips and Variations for Your Zucchini Casserole
• Frequently Asked Questions About Cheesy Zucchini Casserole
• Recipes You May Like
• Let's Wrap This Up
• Cheesy Zucchini Casserole

That night, I made this cheesy zucchini casserole for the first time, and Donald actually put down his phone mid-bite and said, "Wait, what is this?" Coming from a man who eats everything quietly, that was basically a standing ovation.

The best part? It tastes like pizza. Layers of tender zucchini, rich marinara sauce, and bubbling mozzarella come together in one baking dish, and it comes out of the oven smelling like your favorite Italian restaurant. Alex, who has been skeptical of vegetables since roughly age six, asked for seconds. I nearly fell over.

If you love easy veggie sides that actually taste good, you might also want to check out my easy zucchini casserole dinner for another simple weeknight spin on this veggie.

Why You Will Like This Recipe

This cheesy zucchini casserole checks so many boxes for a busy weeknight or a relaxed Sunday dinner. Here is why it has become one of my most-made side dishes:

• Ready in about 50 minutes with simple steps anyone can follow
• Uses just a handful of real ingredients you probably already have
• Tastes like cheesy pizza, which means even picky eaters tend to love it
• The salting and draining step keeps it from getting watery (game-changing, seriously)
• Works great as a side dish or a light vegetarian main
• Low in calories at around 132 per serving, which I always appreciate

What You Need for This Cheesy Zucchini Casserole

• Olive oil spray
• 6 medium zucchini (about 2 pounds), unpeeled
• 1 teaspoon kosher salt (or ½ teaspoon of any other salt)
• 1 cup marinara sauce (I use Rao's, it makes a difference)
• ¼ teaspoon black pepper
• 1 teaspoon dried oregano
• 1 teaspoon garlic powder
• 1 ½ cups part-skim shredded mozzarella, divided (6 ounces total)
• 2 tablespoons grated Parmesan

A note on substitutions: You can swap the marinara for a simple homemade tomato sauce if you have one on hand. For the mozzarella, whole-milk mozzarella works too and gets even gooier, which Alex absolutely loves.

How to Make This Cheesy Zucchini Casserole Step by Step

Step 1: Prep Your Zucchini

Preheat your oven to 400°F.

Spray a 2-quart baking dish with olive oil spray and set it aside.

Slice your zucchini into ½-inch thick rounds. You want them thick enough to hold up in the oven without turning mushy.

Sprinkle the slices generously with salt, then place them in a colander over the sink. Let them sit and drain for 30 minutes at room temperature.

I know, the waiting is hard. But please do not skip this step. It draws out the extra moisture in the zucchini, and that is the whole reason this casserole stays thick and cheesy instead of watery and sad. I learned this the hard way the first time I made it (I was impatient and the result was basically zucchini soup. Not cute).

Step 2: Mix Everything Together

Once your zucchini has drained, transfer the slices to a large bowl.

Add the marinara sauce, black pepper, dried oregano, garlic powder, and 1 cup of the shredded mozzarella. Toss everything together until the zucchini is well coated.

This is the moment it starts to smell amazing. Oregano, garlic, and tomato sauce together in one bowl? Yes please.

Step 3: Assemble and Bake

Pour the zucchini mixture into your prepared baking dish and spread it out into an even layer.

Sprinkle the remaining ½ cup of mozzarella over the top, then finish with the grated Parmesan.

Bake uncovered at 400°F for about 30 minutes, until the cheese is golden and bubbly on top.

Your kitchen is going to smell unbelievable at around the 20-minute mark. Fair warning.

Step 4: Let It Rest Before Serving

This part matters more than you might think. Pull the casserole out of the oven and let it rest for 10 minutes before serving.

Like most baked dishes, it firms up a little as it cools and tastes way better warm than piping hot straight from the oven. Donald always says it reminds him of a deep-dish pizza without the crust, and honestly? He is not wrong.

Storage and Reheating

To store: Let the casserole cool completely, then cover the baking dish tightly with plastic wrap or transfer portions to an airtight container. It keeps well in the refrigerator for up to 3 to 4 days.

To reheat: The oven is your best friend here. Reheat portions at 350°F for about 10 to 15 minutes until warmed through and the cheese gets melty again. You can also use the microwave in a pinch, but the texture is better from the oven.

Does it freeze? See the FAQ section below for my honest take on that one.

One thing I love about this dish is that the flavors actually get a little better the next day. The oregano and garlic really settle in overnight, so leftovers are genuinely something to look forward to.

Tips and Variations for Your Zucchini Casserole

Do not skip the draining step. I already mentioned it, but it is worth saying again. Thirty minutes feels long, but it makes all the difference between a thick, cheesy casserole and a watery mess.

Want to add protein? Stir in some cooked Italian sausage or shredded rotisserie chicken with the zucchini mixture before baking. Sarah loves it with turkey sausage crumbled in.

More veggies? Sliced mushrooms or diced bell peppers mix in really well. Just make sure they are not too wet or they will add extra liquid.

Spice it up. A pinch of red pepper flakes added to the zucchini mixture gives it a little heat that I personally love.

Cheese swaps. Provolone instead of mozzarella gives it a slightly sharper, richer taste. Fontina is also wonderful if you want something a little fancier.

Wondering if you could make this into more of a full meal? Serve it alongside some crusty garlic bread and a simple green salad. That is one of our go-to weeknight dinners when I want something satisfying but not heavy.

Frequently Asked Questions About Cheesy Zucchini Casserole

How do you keep zucchini casserole from getting watery?

The salt-and-drain method is the real answer here. When you slice the zucchini and sprinkle it with salt, you are pulling the excess water out before it even hits the oven. Let the slices sit in a colander for a full 30 minutes and you will be amazed at how much liquid comes out. That one step is what keeps the casserole thick and scoopable instead of soupy. Some people also pat the slices dry with a paper towel after draining, which is an extra precaution I occasionally take when my zucchini feels especially watery.

Can I make cheesy zucchini casserole ahead of time?

Yes, and it works really well. You can assemble the whole casserole the night before, cover it tightly, and keep it in the refrigerator. When you are ready to bake, just pull it out while the oven preheats and add a couple of extra minutes to the baking time since it will be going in cold. I have done this on Sunday afternoons when I know Monday dinner is going to be hectic, and it is such a relief to just slide it straight into the oven.

What can I serve with cheesy zucchini casserole for dinner?

This casserole is really versatile as a side dish. It pairs beautifully with simple grilled chicken, baked salmon, or even a plate of pasta. We have also served it alongside a big green salad and some warm bread for a completely vegetarian dinner, and nobody felt like anything was missing. Donald actually said it was one of the better weeknight dinners we have had recently, which made me very happy.

Can I freeze zucchini casserole after baking?

Honestly, I would not recommend it. Zucchini has a very high water content, and once it is frozen and thawed, the texture turns quite soft and watery even after doing the draining step. It just does not hold up the same way. The good news is it keeps well in the fridge for several days, so you are better off storing it there and eating it within the week. If you do want to try freezing it, freeze individual portions and reheat them directly from frozen in a 375°F oven for the best chance of a decent result.

Recipes You May Like

If this cheesy zucchini casserole is your kind of recipe, you might also enjoy these:

• Cheesy Chicken Broccoli Rice Casserole - another cozy baked casserole that is hearty enough to be dinner on its own
• Creamy Baked Mac and Cheese - because when you want something cheesy, bubbly, and completely satisfying, this one never lets you down
• One Pot Cheesy Chicken Broccoli and Rice Casserole - a simple, filling one-dish dinner for busy nights when you want something warm and homemade

Let's Wrap This Up

This cheesy zucchini casserole is one of those recipes that feels too simple to be this good. A handful of ingredients, one baking dish, and about 50 minutes later you have something that looks and tastes like it took way more effort than it did.

The secret, as always, is in the little details. Salt your zucchini, let it drain, do not rush the rest time at the end. Those three things are what take this from good to really, really good.

I hope your family loves it as much as mine does. And if Alex, the world's most reluctant vegetable eater, asks for seconds at your house too, I want to hear about it!

Save this one to Pinterest so you can find it easily, and let me know in the comments how it turned out for you.

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