Easy Yellow Squash Casserole Recipe

There's something nostalgic and comforting about the scent of buttery squash and crispy breadcrumbs baking in the oven. This Easy Yellow Squash Casserole is warm, cheesy, and irresistibly creamy—everything a cozy side dish should be.

this Recipe

I first whipped this up one summer when our garden overflowed with yellow squash. What began as a way to avoid wasting fresh produce quickly became a potluck favorite, requested year after year. It’s quick, affordable, and always a hit with kids and adults alike.

Whether you're serving it alongside roasted chicken or bringing it to a holiday table, this casserole is a no-fail, crowd-pleasing classic. Let’s take a look at why you’ll want to make it on repeat.

Why You’ll Love This Easy Yellow Squash Casserole

Once you try this casserole, you’ll understand why it’s a Southern staple. It delivers that perfect blend of creamy, cheesy comfort with just the right amount of crunch.

First off, it's incredibly easy to make. You don’t need any fancy ingredients or special skills—just a few simple steps, and you’ve got a bubbling casserole ready to impress.

It’s also budget-friendly. Yellow squash is one of the most affordable vegetables at the market, especially in season. Add pantry staples like eggs, cheese, and breadcrumbs, and you’ve got a full dish for under $10.

This casserole is the ultimate make-ahead side dish. You can prep it earlier in the day or even the night before, then just pop it in the oven when you’re ready. Perfect for busy holidays or weeknight dinners.

And did I mention it’s family-approved? Even picky eaters who claim they “don’t like squash” tend to clean their plates. It’s mild, creamy, and cheesy—what’s not to love?

Let’s dive into the key ingredients that make this dish shine.

Ingredients Notes

The beauty of this Easy Yellow Squash Casserole is that it starts with a handful of wholesome, accessible ingredients that work together in delicious harmony.

Yellow squash is the star of the show here. Look for firm, bright yellow squash without blemishes. Medium-sized squash tend to be more flavorful and less watery than oversized ones. Slice them thin so they cook evenly and melt into the creamy filling.

Onion brings savory depth to the dish. I like using sweet yellow onion for balance, but white or even red onions will do in a pinch. Make sure to sauté it until soft and translucent to bring out its natural sweetness.

Sharp cheddar cheese is a must for richness and that classic Southern casserole flavor. It melts beautifully into the filling and adds that gooey texture everyone loves. You can mix in a bit of Parmesan for extra punch if you like.

Eggs and sour cream create the creamy base that binds everything together. The eggs help the casserole set, while the sour cream keeps it moist and tangy. Some folks swap in mayonnaise or Greek yogurt—both work well if you prefer.

Breadcrumbs and butter top it all off with a golden, crunchy crust. I like using plain breadcrumbs mixed with a little melted butter and a pinch of salt. Crushed Ritz crackers are a classic Southern twist if you want extra buttery crunch.

As for equipment, you’ll need a large skillet for sautéing, a mixing bowl, and a standard 9x13-inch baking dish. Nothing fancy—just kitchen basics.

How To Make This Easy Yellow Squash Casserole

Making this casserole is a breeze, even if you’re short on time. Here's how it comes together, step by step.

Start by preheating your oven to 350°F. While the oven heats, slice your squash into thin rounds and dice your onion. You’ll want to keep the slices fairly uniform so they cook evenly and blend seamlessly into the casserole.

In a large skillet over medium heat, melt a little butter and sauté the squash and onion together. This step is important—it helps reduce moisture and concentrate the flavors. Cook them for about 10–12 minutes, stirring occasionally, until the squash is tender and the onions are translucent.

Once the squash mixture is soft and lightly golden, remove it from the heat and let it cool slightly. In a separate bowl, whisk together your eggs, sour cream, shredded cheese, and a bit of salt and pepper. Then, gently fold in the sautéed squash and onions until everything is well coated.

Transfer the mixture to a greased 9x13-inch casserole dish, spreading it out evenly. Now for the best part: the topping. Mix your breadcrumbs (or cracker crumbs) with melted butter, then sprinkle them generously over the top. This is what gives the casserole that irresistible crunch.

Bake the casserole for 25–30 minutes, or until the top is golden brown and the center is set. The edges will be bubbling slightly, and your kitchen will smell amazing. Let it rest for a few minutes before serving to allow everything to firm up.

Total time, start to finish, is just about 45 minutes—perfect for busy nights or stress-free holiday cooking.

Storage Options

This yellow squash casserole stores like a dream, making it perfect for leftovers or prepping ahead.

Once cooled, you can cover the dish tightly with foil or transfer leftovers into airtight containers. It will keep in the fridge for up to 4 days without losing flavor or texture.

To freeze, let the casserole cool completely. Wrap it tightly with plastic wrap and then foil, or store portions in freezer-safe containers. It will keep well for up to 2 months. Thaw overnight in the fridge before reheating.

When you’re ready to reheat, pop it in a 350°F oven, covered, for about 15–20 minutes (or until heated through). For individual servings, the microwave works great—just be sure to cover it so it doesn’t dry out.

Variations and Substitutions

One of the things I love most about this casserole is how adaptable it is. Whether you’re working with dietary needs or cleaning out the fridge, it’s easy to tweak.

If you're avoiding dairy, swap out the sour cream for a dairy-free version and use your favorite plant-based cheese. Just note that the texture may vary slightly.

Want a heartier dish? Add cooked bacon or crumbled sausage to the filling. Both bring an extra layer of flavor and make the casserole feel more like a main course.

For extra veggies, try mixing in chopped spinach, zucchini, or even shredded carrots. Just be sure to sauté them with the squash to reduce moisture.

Prefer a low-carb version? Skip the breadcrumb topping and sprinkle with a little extra cheese instead. You’ll still get a golden crust without the added carbs.

And of course, you can swap in crushed Ritz crackers, panko, or even cornflakes for the topping depending on what you have on hand. Don’t be afraid to get creative!

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