Every summer, my garden does this thing where it produces way more squash than any two people could reasonably eat. I’m talking countertops covered, a bag dropped on the neighbor’s porch, and still more coming in the next morning. Last August I hit a wall. There were nine yellow squash sitting in a bowl on the counter and I had zero interest in sauteing them plain again or throwing them in another stir-fry. So I pulled this recipe out of my back pocket. I’d made it once years ago at a church potluck and honestly forgotten about it until that moment. One bite reminded me exactly why I scribbled it down in the first place. Creamy, cheesy, a little crunchy on top, and it uses up a serious pile of squash without feeling like you’re just getting rid of vegetables. My husband asked for it three times that week. I didn’t argue once.

What You’ll Need

• 3 medium yellow squash, sliced into 1/4-inch rounds
• 1 medium yellow onion, diced
• 1 medium red bell pepper, diced
• 2 1/2 tablespoons butter, divided
• 2 eggs
• 1/3 cup mayonnaise
• 1/4 cup sour cream
• 1 1/2 cups shredded cheddar cheese, divided
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1 cup crushed butter crackers (like Ritz)

How to Make It

1. Preheat and prep.

Start by preheating your oven to 350°F. Go ahead and grease a medium baking dish with a little butter or cooking spray and set it aside. Getting the oven going early means it’s ready when you are, and there’s nothing worse than a finished casserole sitting on the counter waiting for the oven to catch up.

Slice your squash into thin rounds, about a quarter inch thick. You want them thin so they cook through in the skillet without turning to mush later in the oven. If some slices are a little thicker, just break them up with your spoon when you’re sauteing. Dice the onion and red bell pepper into small, even pieces. Smaller is better here because you want everything to blend into the casserole rather than sit in big chunks that remind you you’re eating vegetables.

2. Saute the vegetables.

The sauté step is what separates a great squash casserole from a soggy, watery disappointment. Melt about 1 1/2 tablespoons of butter in a large skillet over medium heat. Add the squash, onion, and bell pepper all at once. Stir them around every couple of minutes and let them go for 8 to 10 minutes. The squash will soften and release a surprising amount of water as it cooks. That’s exactly what you want happening in the skillet instead of the oven. Cooking off that moisture now means your casserole sets up properly and doesn’t turn into a puddle once it bakes. Season with salt and black pepper once everything is tender, give it one more stir to make sure the seasoning is evenly distributed, then pull it off the heat. Let the mixture sit for at least five minutes before you move on. Rushing this step is how you end up with scrambled eggs in your casserole.

3. Mix the filling.

While the vegetables are cooling, grab a large mixing bowl and whisk together the eggs, mayonnaise, sour cream, and 1 cup of the cheddar cheese until it’s smooth and well combined. The mayonnaise and sour cream together create something really creamy and slightly tangy that balances the richness of all that cheese. It doesn’t taste like mayo when it’s done baking, I promise. Fold the cooled squash mixture into the bowl gently. You don’t want to overmix because you’re after a casserole with some texture, not a puree. A few careful folds and you’re done. The mixture should look creamy with visible pieces of squash and pepper throughout.

4. Assemble and add the topping.

Pour the mixture into your prepared baking dish and spread it out evenly with a spatula so it bakes at the same rate across the whole dish. Now for the topping, which is genuinely the best part of this whole situation. Sprinkle the remaining half cup of cheddar cheese in an even layer across the top, then cover the whole thing generously with crushed butter crackers. Don’t press them down. Just let them sit on top loosely. As the casserole bakes, the crackers soak up just a little heat and butter from below and toast into this golden, crunchy layer that contracts beautifully with the soft filling underneath. You’ll catch yourself picking pieces off the top before it even makes it to the table.

5. Bake and rest.

Bake uncovered for 30 to 35 minutes. You’re looking for a deep golden brown top and edges that are just barely pulling away from the sides of the dish. The center should be set, not jiggly when you give it a gentle shake. If the crackers are browning too fast before the center is done, lay a piece of foil loosely on top for the last few minutes. Pull it out and let it rest for five full minutes before you dig in. That resting time matters more than it sounds. It firms up just enough to scoop cleanly and hold together on the plate.

If you’re already a fan of casseroles that lean sweet and savory, my pineapple casserole uses a similar buttery cracker topping and is just as addictive. And if you want something with more heft on a weeknight, the sausage green bean and potato casserole is a full meal in one dish.

One more thing worth knowing: this reheats really well. The top won’t stay as crispy, but a few minutes in a 300°F oven brings it back pretty close to fresh. Day two leftovers are genuinely good. I say that as someone who is usually the first to admit when leftovers don’t hold up.

Quick Tips

• Don’t skip the sauté. Raw squash will release too much water in the oven and make the casserole soupy.
• Cool the vegetables before mixing. Hot squash folded into eggs scrambles them. A few minutes off the heat makes all the difference.
• Crush the crackers coarsely. Small crumbs melt into the cheese rather than staying crispy. Leave some texture in there.