Cheesy Yellow Squash Casserole

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Yellow squash casserole is one of those side dishes that earns a spot at every table, from a simple weeknight dinner to the holiday spread. This version is creamy, cheesy, and topped with a buttery cracker crust that comes out of the oven golden and crisp every single time.

Yellow Squash Casserole Recipe Ingredients

• Yellow squash: Fresh summer squash works best here. Look for smaller to medium squash as they tend to have fewer seeds and a better texture in the finished casserole.
• Butter: This is what you cook the squash in, and it matters. Butter adds flavor from the start that oil just doesn’t give you.
• Salt and pepper: Season the squash while it cooks, not after. It draws out moisture and builds flavor right in the pan.
• Sweet or Vidalia onion: Diced small so it cooks down completely with the squash. Vidalia is the classic choice here and adds a mild sweetness without overpowering the dish.
• Cheddar cheese: Use a block and shred it yourself, if you can. Pre-shredded cheese has a coating that keeps it from melting as smoothly into the filling. (My mom always used this shortcut, and it is still delish.)
• Egg: Beaten into the sour cream mixture, it binds the filling and gives the casserole structure so it holds together when you scoop it.
• Sour cream: This is what makes the filling creamy without being heavy. Full fat gives you the best result.
• Crackers: I use Ritz crackers most of the time. They bake up golden and buttery and give you that signature crunch. My mom always uses Saltine crackers. Both are delicious. For a gluten-free version, swap in gluten-free butter crackers or omit the topping altogether.

Helpful Tools

• Good knives are a must in the kitchen for any home cook. I have fallen in love with Kyocera ceramic knives. I have the 5 inch, 7 inch , and a pairing knife!
• A cutting board is also essential! I use a nice large woodeb board almost every day and also keep a utility board on hand too! As long as they are nice and sturdy they will make cutting an easy task in the kitchen.
• A large skillet is my go to tool for my kitchen. My favorite is cast iron, but I always have a nonstick skillet too. I like something with a heavy bottom and high sides.
• A classic baking dish is a must have. They don’t have to be fancy. I find I use my standard glass pyrex a lot. They often have lids and are easy to store leftovers or take to a potluck.  I also like stoneware baking dishes. They cook wonderfully and keep your food warmer for a longer period of time.

How to Make Squash Casserole

✱ Below shows step-by-step photos and instructions. For the complete recipe, along with ingredient amounts, scroll down to the recipe card.

Step 1 | Prep and Cook the Squash

Preheat your oven to 350 degrees and butter or lightly spray an 11 X 7 baking dish.

Melt butter in a skillet over medium-high heat and add the sliced squash, diced onion, salt, and pepper. Cook, stirring occasionally, for about 10 minutes until the squash is tender and most of the moisture has cooked off. I like to keep a little structure to some of the squash (not mushy).

You want it to look a little dry in the pan, not soupy.

Drain well before moving on.

Step 2 | Mix the Filling

In a large bowl, beat the egg.

Then stir it together with the sour cream and 1 ½ cups of shredded cheddar.

Fold in the cooked and drained squash until everything is evenly combined.

Step 3 | Make the Cracker Topping

In a small bowl, combine the crushed Ritz crackers with melted butter and stir until the crackers are evenly coated.

Step 4 | Assemble the Casserole

Pour the filling into your prepared baking dish and top with the remaining cheese. Sprinkle the buttered crackers evenly over the top.

Step 5 | Bake

Bake for 25 to 30 minutes until golden and bubbly. Let the casserole rest for 5 to 10 minutes before serving.

Summer Squash Casserole Variations

One of the things I love about this squash casserole is how easy it is to make it your own. Here are a few of my favorite ways to switch it up.

• Switch up the cheese: I am a cheddar girl through and through, but a little Monterey Jack, Colby, or even a sprinkle of Parmesan in the topping is delicious.
• Use bacon grease in place of the butter in the squash mixture. It ads a whole different flavor to the casserole.
• Bring in more veggies: If you like, add in a little diced bell pepper sauteed right along with the squash and onion, which adds color and a little extra sweetness.
• Make it a meal: Stir in some cooked, crumbled bacon or diced ham for a heartier, protein-rich dish that can hold its own at the center of the table.
• Give it a kick: If your family likes a little heat, a pinch of red pepper flakes or some diced jalapeno stirred in brings the heat and the flavor!
• Cheese Mixture: If you’d like to skip the layer of cheese on top. Use 2 cups of cheese in the squash mixture, and omit the top layer.
• Change up the topping: Ritz crackers are classic and what I reach for, but crushed cornflakes, buttery crackers, or even crushed potato chips all give you that golden, crunchy top.

Gluten-Free Squash Casserole:

This recipe is easy to make gluten-free. Swap the Ritz crackers for gluten-free butter crackers, gluten-free panko, or gluten-free breadcrumbs mixed with a little melted butter to get the same golden, crunchy topping. You can also skip the topping altogether and finish with just the cheese. Everything else in this recipe is naturally gluten-free. Always check labels carefully if you are cooking for someone with celiac disease, since cross-contamination can happen with packaged foods.