Our summer squash casserole recipe is creamy, cheesy, and packed with summer squash and topped with a butter cracker crust that makes every bite a moan-worthy event.
It’s the perfect accompaniment for many of your favorite dishes and a great way to use up the bounty of summer squash from your garden or local farmers’ market.
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You’ll love how fast this Southern classic comes together, and the end results are well worth the time it takes to prepare, especially when you see the smiling faces enjoying this delicious side dish.
With layers of tender summer squash, a cheesy, creamy filling, and a buttery golden cracker topping, our summer squash casserole is pretty much irresistible.
Made with simple ingredients, our cheesy squash casserole recipe is definitely a crowd pleaser.
Serve it with our Homemade Cornbread and our 7 Layer Salad for a light summer Southern-style meal that your whole family will love!
Ingredients
Gather the ingredients to prepare our Summer Squash Casserole recipe. Culinary professionals call this the “Mise en Place,” which means “everything in its Place.”
Setting up your ingredients not only helps speed up the cooking process but also ensures you have all the necessary ingredients on hand to make the recipe.
Can I Make Adjustments to the Recipe?
Absolutely. We made our Squash Casserole with yellow squash, but you can use zucchini or a mix of both.
You can also add other veggies to the mix. Spinach, red bell peppers, and mushrooms would all be nice additions to the recipe.
I love cheddar cheese, but you can use just about any cheese you enjoy eating. Monterey Jack, smoked Gouda, Swiss cheese, and Gruyere all would be delicious substitutions. Or combine a mix of your favorites to make the recipe.
To kick up the heat, try adding red pepper flakes, a little cayenne, or a dash or two of your favorite hot sauce.
How to Make Squash Casserole
Follow along with my simple step-by-step instructions to learn how to make Squash Casserole in your home kitchen.
- Clean and rinse the yellow squash under cold running water. Then pat them dry with a paper towel to remove any excess moisture.
- Place the crackers in a ziplock bag.
- Use a rolling pin to break the crackers into small pieces.
- Add the crackers, melted butter, Romano cheese, and chopped parsley to a small bowl.
- Use a fork or a spoon to mix the melted butter and cheese into the crushed crackers.
- Using a sharp knife, slice the squash into half-inch slices.
*Keep the slices uniform in size, so they cook at the same rate. - Add two tablespoons of butter to a large skillet or cast-iron pan over medium heat.
Preheat the oven to 350°F.
- When the butter is melted, add the chopped onions and sliced yellow squash to the pan.
- Cook for about 5 minutes or until the onions and squash become slightly tender. Stir frequently to prevent burning.
- Add the garlic and fresh thyme to the pan and sauté until the garlic becomes fragrant (1-2 minutes).
- Remove the pan from the heat and, using a slotted spoon, remove the squash and onion mixture from the pan. Place the mixture on a paper towel-lined baking sheet to let it drain off the excess liquid and oil.
- Set aside until needed, allowing it to cool to room temperature. Do not tent the squash.
- Add the salt, black pepper, beaten egg, sour cream, sharp cheddar cheese, and mayonnaise to a large mixing bowl.
- Whisk together to combine.
- Add the squash to the sour cream mixture.
- Use a rubber spatula or a spoon to gently fold the ingredients together, ensuring the squash is fully coated.
- Lightly grease a medium baking dish, then add the squash mixture to the dish. Spread the mixture in an even layer.
- Sprinkle the cracker crumb mixture evenly over the squash mixture.
- Place the baking dish on the center rack of the preheated oven and bake for 25-30 minutes until the casserole is bubbly and the cracker crust is golden brown.
- Let the casserole sit for 5 minutes before serving.
Our squash casserole is perfect for a Sunday dinner, family gathering, potluck, or anytime you want to add some down-home deliciousness to your table.
I guarantee that after the first bite, they’ll be lining up for seconds.
How to Store and Reheat
Let the leftover squash casserole cool to room temperature before storing. Transfer it to an airtight container or cover the casserole dish tightly with plastic wrap or aluminum foil, and refrigerate for 2-3 days.
To reheat, place the casserole in a 350-degree oven for 15 to 20 minutes, or until warmed through. You can also microwave individual portions, but the Ritz cracker crumbs will lose their crunch.
This dish does not freeze well due to the creamy filling and high water content in the squash.
Recipe FAQs
Yes, you can. It can be made the day before and stored covered in the fridge. Don’t bake it too far in advance; it’s best to bake before serving so the cracker topping stays crisp and the casserole bakes up fresh and bubbly.
Yellow squash is naturally mild, so seasoning is key. Our recipe features sweet onions, garlic, fresh thyme, and the perfect amount of salt to bring out those savory flavors. I wouldn’t advise tasting the filling before baking because of the raw egg, so follow the recipe closely and trust the process.
Squash is naturally watery, and it’s important to drain off any excess water that didn’t cook off. Check the mixture after it cools before adding it to the filling. It only takes a little excess water to throw off the texture, so don’t skip that step.
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Squash Casserole Recipe
Ingredients
Cracker Topping
- 1 sleeve Ritz crackers About 32 crackers( you can use any cracker you prefer).
- 3 tablespoons unsalted butter melted
- ¼ cup grated romano cheese or parmesan
- 2 teaspoons Italian Parsley
Squash Casserole
- 3 cups yellow squash about 4 medium-sized squash
- ½ cup sweet onion diced
- 1 tablespoon garlic chopped
- 2 teaspoons fresh thyme chopped
- 1 cup sharp cheddar cheese
- 1 large egg lightly beaten
- ¾ cup sour cream room temperature
- ¼ cup mayonnaise room temperature
- 2 tablespoons unsalted butter
- 1 ½ teaspoons table salt
- ½ teaspoon black pepper
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Instructions
Cracker Topping
- Place the crackers in a ziplock bag. Use a rolling pin to break the crackers into small pieces.
- Add the crackers, melted butter, Romano cheese, and chopped parsley to a small bowl.
- Use a fork or a spoon to mix the melted butter and cheese into the crackers pieces.
Squash Casserole
- Clean and rinse the yellow squash under cold running water. Then pat them dry with a paper towel to remove any excess moisture.
- Using a sharp knife, slice the squash into half-inch slices.*Keep the slices uniform in size, so they cook at the same rate.
- Preheat the oven to 350 degrees
- Place a large skillet or cast iron pan on the stovetop over medium heat.
- Add 2 tablespoons of butter to the hot pan and stir until melted.
- Add the chopped onions and sliced yellow squash to the pan.
- Cook for about 5 minutes or until the onions and squash become slightly tender. Stir frequently so they don't burn.
- Add the garlic, fresh thyme, to the pan and saute until the garlic becomes fragrant (1-2 minutes).
- Remove the pan from the heat and, using a slotted spoon, remove the squash and onion mixture from the pan. Place the mixture on a paper towel-lined baking sheet to let it drain off the excess liquid and oil.
- Set aside until needed, allowing it to cool. Do not tent the squash.
- Add the salt, black pepper, beaten egg, sour cream, sharp cheddar cheese, and mayonnaise to a large mixing bowl
- Whisk together to combine.
- Add the squash to the sour cream mixture. Use a rubber spatula or a spoon to fold the ingredients together, fully coating the squash.
- Lightly grease a medium baking dish, then add the squash mixture to the dish. Spread the mixture in an even layer.
- Sprinkle the cracker crumb mixture in an even layer overtop of the squash mixture.
- Place the baking dish on the center rack of the preheated oven and bake for 25-30 minutes until the casserole is bubbly and the cracker crust is golden brown.
- Let the casserole sit for 5 minutes before serving.
Peter vermiglio says
Delicious!
Patricia Lukas says
Just the recipe I needed! I have a farm share this summer and yellow squash was in this week’s haul.
I remember eating this dish at a restaurant in Berryville, Virginia in the 1960s.
Chef Dennis Littley says
Let me know how you like it.