Squash Casserole

Creamy, cheesy, and topped with a buttery cracker crust, this squash casserole is a comfort food classic that's especially welcome during summer squash season. It's one of the best ways to use up an abundance of fresh yellow squash, and it's always a hit at cookouts and potlucks. Serve it alongside chicken-fried chicken, grilled pork chops, barbecue ribs, or just about any backyard favorite, and don't be surprised if everyone goes back for seconds.

This casserole starts with tender yellow squash and sweet onion, which are folded into a rich mixture of eggs, sour cream, mayonnaise, sharp cheddar, and fresh thyme. After the casserole begins baking, it's topped with a buttery mixture of crushed crackers and Parmesan cheese that turns irresistibly crisp and golden in the oven. The contrast between the creamy filling and crunchy topping is what makes this old-fashioned recipe so memorable. Even better, you can prepare it ahead of time and refrigerate it until you're ready to bake, making it an easy side dish for entertaining or busy weeknights.

Do you have to cook the squash before adding it to the casserole?

Yep! Unless you want crunchy, watery squash in your casserole, it's best to cook it a bit before assembling the casserole. Luckily, this recipe keeps the cooking easy and hands-off. You just add the sliced squash and chopped onion to a sheet tray with a little olive oil, salt, and pepper and roast it in the oven for about 25 minutes.

How do you keep squash casserole from getting watery?

It's important to salt, par-cook, and drain the squash before assembling the casserole to prevent it from being watery. The mixture of eggs, sour cream, mayonnaise, and cheese also acts as a binder to thicken it. If you want to take an extra step, add 1/2 to 1 cup of cooked white rice into the mix before baking—it helps make a sturdy and thick squash casserole (and turns it into a complete meal).

What crackers are best on top of squash casserole?

Buttery round crackers (aka Ritz crackers) are flaky and delicious on this casserole, but feel free to substitute any salty, crispy cracker, such as classic saltine crackers or even cheese-flavored crackers such as Cheez-Its.

Can you freeze squash casserole?

Because squash contains a lot of moisture, freezing is not recommended. When the casserole freezes and then thaws, it releases even more liquid, which can make it runny and soggy. However, this squash casserole can be stored in the refrigerator for up to 4 days after baking.

How to Make Squash Casserole

INGREDIENTS

• Yellow squash: The star ingredient, yellow squash (also called summer squash) has a mild, slightly sweet flavor and tender, buttery texture as it bakes.
• Yellow onion: This brings savory sweetness and depth that complements the squash.
• Olive oil: Softens the vegetables while adding richness and helping them cook evenly.
• Eggs: These add a light custardy texture as the casserole bakes and help bind the filling so it sets.
• Sour cream: This adds tangy flavor and creates a creamy, luscious filling. If you don’t have any on hand, you can swap in full-fat Greek yogurt.
• Mayonnaise: The classic sandwich spread contributes richness and a silky texture, while helping keep the casserole moist.
• Sharp cheddar cheese: Cheddar provides bold, cheesy flavor and a gooey texture that pairs well with the mild squash. Monterey jack cheese also works well here.
• Fresh thyme: This adds a bright, earthy note that balances the rich filling. Parsley, chives, or rosemary are all tasty substitutes.
• Melted butter: The butter coats the cracker crumbs so they toast evenly in the oven, giving the topping rich flavor and an extra-crispy bite.
• Butter crackers: These bake into a golden, crunchy topping that contrasts with the creamy casserole.
• Parmesan cheese: This is the finishing touch that helps the topping brown all over. Pecorino Romano will also work.

STEP-BY-STEP INSTRUCTIONS

Combine the squash and onion on a baking sheet with a drizzle of olive oil, salt, and pepper and roast it until it starts to soften and release its liquid.

Transfer the roasted squash and onions to a colander and blot the vegetables with paper towels to release any excess moisture.

Whisk the eggs in a large bowl, then add the sour cream, mayonnaise, cheddar cheese, and fresh thyme.

Gently fold the squash and onions into the egg-sour cream mixture.

Transfer the squash mixture to a greased 3-quart baking dish.

To make the crunchy topping, combine some melted butter and parmesan cheese with the crushed crackers in a small bowl.

Spread the casserole with the buttery crushed crackers and bake until golden brown and bubbly.

A full list of ingredients and directions can be found in the recipe below.