Cheesy Zucchini Casserole

Modified: Jul 13, 2026 · Published: Jul 13, 2026 by Rita · This post may contain affiliate links · Leave a Comment

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Cheesy zucchini casserole is an easy baked dish with tender zucchini, melty cheese, and a crispy buttery topping. It's perfect for busy weeknights or whenever you have extra zucchini to use up.

I've found that squeezing the zucchini really well is the secret to a creamy casserole instead of a watery one. It's a simple step, but it makes all the difference.

Slice of cheesy zucchini casserole on a plate with a crispy breadcrumb topping and parsley

Why This Is On Repeat At My House

This casserole makes its way to our table several times every summer, especially when zucchini is in season. It's easy to throw together with simple ingredients I usually already have on hand.

I've found it's one of the easiest ways to get everyone to enjoy zucchini. The cheesy filling and crispy topping disappear fast, and nobody seems to mind that they're eating extra vegetables.

It also fits busy days really well. I can mix everything together while the oven preheats, and I almost always save a portion for lunch the next day because it reheats so well.

🛒 Ingredients

Zucchini - Choose firm, medium-sized ones for the best texture. Be sure to squeeze out as much moisture as possible so the casserole stays creamy instead of watery.
Mozzarella Cheese - Creates the creamy, melty center. Freshly grated melts more smoothly, but pre-shredded works well for convenience.
Parmesan Cheese - Adds a rich, savory flavor throughout the casserole and a little extra on top. Freshly grated gives the best flavor, but either works.
Cheddar Cheese - Brings extra richness and color. Mild cheddar keeps the flavor balanced, while sharp cheddar adds a little more bite.
Eggs - Help hold everything together so each serving scoops out more neatly after baking.
Panko Breadcrumbs - Create the light, crispy topping. Regular breadcrumbs can be substituted, but they won't be quite as crunchy.

👩‍🍳 You'll find the complete list of ingredients below the recipe card.

🥘 How To Make Cheesy Zucchini Casserole Step By Step

Prep the oven: Preheat the oven to 375°F and lightly grease a 3-quart baking dish.
Salt the zucchini: Place the grated zucchini in a colander and sprinkle with the salt. Let it sit for 10 minutes until you see liquid collecting underneath.
Squeeze it dry: Transfer the zucchini to a clean kitchen towel and squeeze out as much liquid as possible. I usually wring it out two or three times. This keeps the casserole creamy instead of watery.
Mix the filling: In a large bowl, combine the zucchini, seasonings, garlic, eggs, Parmesan, mozzarella, and cheddar until evenly mixed. The mixture should look evenly coated and moist, but not dripping wet.

Grated zucchini, eggs, cheeses, garlic, and seasonings in a mixing bowl before stirring

Mixed zucchini casserole filling combined in a glass mixing bowl

Fill the baking dish: Spread the mixture into the prepared baking dish and smooth the top into an even layer so it bakes evenly.
Bake: Bake uncovered for 20 minutes, until the edges are bubbling and the center is mostly set.
Make the topping: Mix the Panko, melted butter, and remaining Parmesan. I like adding a little extra Italian seasoning for more flavor.
Finish baking: Sprinkle the topping evenly over the casserole and bake for 5–10 minutes, until golden brown and crisp. For extra crunch, broil for 1–2 minutes, but watch it closely.
Rest and serve: Let the casserole rest for 5 minutes before serving. It holds together much better and is easier to scoop.

Panko breadcrumb topping mixed with Parmesan in a small glass bowl

Partially baked zucchini casserole before adding the breadcrumb topping

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📋 Important Tips Before You Start

Don't skip squeezing the zucchini. This is the single most important step for preventing a watery casserole.
Grate your own cheese if possible. It melts much more smoothly.
Fresh garlic makes a noticeable difference. I always use it when I have it.
Mix the topping while the casserole bakes to save time.
Make it ahead. Assemble the casserole earlier in the day, refrigerate it, then bake just before dinner.
Let it rest before serving. The slices hold together much better.
Watch the broiler carefully. Breadcrumbs can go from golden to burnt surprisingly fast.

Easy Swaps

Swap mozzarella for Monterey Jack if that's what you have on hand.
Add chopped parsley for extra freshness.
Stir in a pinch of smoked paprika for a slightly smoky flavor.
Use gluten-free breadcrumbs if needed.
Add cooked crumbled bacon if you're serving it as a main dish.
Use yellow squash instead of zucchini for a slightly sweeter flavor.

Slice of cheesy zucchini casserole with a crispy topping served on a plate

What To Serve With Cheesy Zucchini Casserole

This casserole pairs well with simple proteins and fresh sides for an easy, balanced meal.

🍱 Storage Instructions

🍱To Store. Keep leftovers in an airtight container in the refrigerator for up to 4 days.
🥶To Freeze. Cool completely, then wrap well and freeze for up to 2 months. I usually freeze individual portions because they're easy to reheat for lunch.
🕒 To Make Ahead. Assemble the casserole up to one day ahead and refrigerate. Wait to add the breadcrumb topping until just before baking so it stays crisp.
🔥To Reheat. Warm individual servings in the microwave. For the crispiest topping, reheat larger portions in a 350°F oven until heated through.

❓FAQs

Why is my zucchini casserole watery?

Most of the time, not enough moisture was squeezed from the zucchini. I usually wring it out several times with a kitchen towel before mixing everything together.

Can I make this ahead of time?

Yes. Assemble the casserole up to a day in advance and refrigerate it. Add the breadcrumb topping just before baking.

Can I use frozen zucchini?

You can, but thaw it completely and squeeze out every bit of extra moisture before using it.