This Zucchini Squash Casserole is the perfect vegetarian addition to your Thanksgiving dinner. It’s creamy, cheesy, buttery, and topped with the most irresistible Ritz cracker crust. This easy side dish pairs perfectly with just about anything all year long from Thanksgiving turkey, grilled chicken to baked ham, and it’s always one of the first dishes to disappear at potlucks and family dinners.

zucchini and yellow squash in a cheesy casserole with a Ritz cracker crumb topping in a 9x13 white baking dish

The Perfect Anytime Side

There’s something so comforting about a baked vegetable casserole. The tender squash and onions are layered with cheese and baked under a buttery cracker topping until bubbly and golden brown. It’s cozy, and warming- the perfect autumnal recipe.

But this squash casserole is still fresh and light enough to enjoy in the warmer months. If your garden is overflowing with zucchini and yellow squash—or you just couldn’t resist grabbing a few at the farmers market—this Zucchini and Yellow Squash Casserole is the perfect way to use them up.

Plus it’s simple ingredients, inexpensive and comes together in a jiffy.

maple roasted acorn squash

What You’ll Need

Find the full, printable recipe with exact measurements at the bottom of this post. Read on for more details and tips!

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Mandolin– for uniform slices, or a sharp kitchen knife
9×13 Baking dish
Vegetables- Zucchini, Yellow Squash, and a sweet Vidalia Onion
Seasonings– salt, pepper, mustard powder, nutmeg (optional)
Cheese- I’m using shredded cheddar Parmesan cheese (I love the Aldi blend! You can also use shredded cheddar or a mix of cheddar and grated Parmesan.)
Ritz crackers (or any buttery crackers)
Grated Parmesan cheese
Butter

shop the ingredients at walmart

How To Make It

Preheat the oven to 350°F.

Slice the vegetables: Using a mandolin or sharp knife, slice the zucchini and yellow squash into ¼-inch rounds. Thinly slice the onion.

Layer the casserole:

In a 9×13 baking dish, layer ⅓ of the squash and zucchini, followed by 1/2 of the onions.
Season with salt, pepper, mustard powder, and nutmeg (if using).
Sprinkle half of the shredded cheese over top.
Repeat the layer with another 1/3 of the squash, zucchini, remaining onions, and seasonings, then the remaining cheese.
Finish with the last layer of squash, zucchini, and seasonings.

Make the topping:

Crush the Ritz crackers in a zip-top bag using a rolling pin or meat mallet.
Add the grated Parmesan cheese and melted butter, then mix until the crackers are evenly coated.
Spread the mixture evenly over the top of the casserole.

Bake:

Cover tightly with foil and bake for 45 minutes.
Uncover and bake an additional 15 minutes, until the vegetables are fork-tender (but not mushy) and the topping is golden brown.

Serve:
Serve warm and enjoy that perfect combination of cheesy, buttery, and savory goodness!

Did you enjoy this recipe? Take a picture and tag me @StephGigliotti on social media and #StephRealLife. I would absolutely love to see your finished dish!

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Variations

Add protein: Stir in some cooked, shredded chicken or crumbled bacon for a heartier casserole.
Mix up the cheese: Try Gruyère, Monterey Jack, or mozzarella for a different flavor twist.
Make ahead: You can slice the veggies and crush the crackers a day in advance. Just store them separately and assemble when ready to bake.
Storage: Store any leftovers covered in the refrigerator for up to 3 days. Reheat in the oven at 350°F until warmed through to keep the cracker topping crisp.

More Delicious Sides

Deceptively Delicious

This Zucchini and Yellow Squash Casserole is one of those recipes that looks simple but tastes so special. It’s the kind of dish that makes everyone at the table say, “What’s in this?!” and then go back for seconds. Whether you’re feeding your family on a weeknight or serving guests for Sunday dinner, this is one side dish that’s sure to steal the spotlight.