Southern Yellow Squash Casserole
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This creamy yellow squash casserole recipe is a classic Southern recipe made with cheddar, Swiss, and Ritz topping. Easy, cheesy, it’s a perfect summer side dish!
Looking for a comforting, creamy, and cheesy summer side dish? This Yellow Squash Casserole is everything you need to turn fresh squash into a warm, bubbly, golden bake. With layers of tender yellow squash, tangy sour cream, sharp cheddar, Swiss cheese, and a buttery Ritz cracker topping.
Whether you’re using squash from your garden or grabbing a few at the market, this classic squash casserole recipe is perfect for potlucks, holidays, weeknight dinners, or any time you crave a creamy vegetable casserole that’s simple but satisfying.
Want to switch it up, give out cheesy baked zucchini casserole a try as well!
Ingredients You’ll Need
- Unsalted butter – We prefer unsalted butter since we add kosher salt, but you can use salted butter just make sure to add less salt to compensate.
- Yellow squash – Yellow summer squash sliced into 1/4 inch circles is the base of the recipe. Save a little to make our One Pot Summer Vegetable Pasta.
- Yellow onion – These are slightly sweet after being sauteed.
- Eggs – Eggs act as a binder for the casserole holding it all together.
- Sour cream – The slightly tangy flavor of the sour cream pairs well with the vegetables.
- Mayonnaise – a little mayo adds creaminess to the casserole.
- Cheese – Sharp cheddar cheese and Swiss cheese blend together to make a delicious creamy filling and topping.
- Ritz crackers – the crackers are both a part of the filling and a delicious buttery topping.
- Seasoning – Black pepper and Kosher salt bring out the flavors in the casserole.
Step‑by‑Step Instructions
Step 1 – Prep. Preheat your oven to 350°F. Lightly spray an 11×7-inch baking dish with cooking spray or brush with butter.
Step 2 – Sauté the Squash & Onion. In a large skillet over medium-high heat, melt 3 Tbsp butter. Add sliced squash, chopped onion, and 1 tsp salt. Cook for 5–7 minutes, stirring occasionally, until the squash is tender but not mushy. Note: You may need to do this in batches. If so, divide the butter and squash into two batches and cook as instructed.
Step 3 – Drain Excess Moisture. Transfer mixture to a strainer and let the excess liquid drain. Press gently with a spoon or plate to remove extra moisture—this helps prevent a watery casserole.
Step 4 – Mix the Base. In a large mixing bowl, whisk together the remaining salt, eggs, sour cream, mayonnaise, cheddar cheese, Swiss cheese, black pepper, and 1 cup of Ritz crackers.
Step 5 – Combine with Squash. Gently fold in the sautéed squash and onions until everything is coated.
Step 6 – Assemble in Dish. Spoon mixture into the prepared baking pan, spreading evenly. Sprinkle with remaining crushed crackers, then top with the remaining cheddar cheese (4 oz).
Step 7 – Bake to Perfection. Bake uncovered for 20–25 minutes until bubbly and golden brown on top.
Step 8 – Rest & Serve. Remove from oven and let rest for 10 minutes. This helps the casserole set, making it easier to serve.
Frequently Asked Questions (FAQs)
Absolutely! Zucchini works just as well. Combine both if you like variety—or use one type. The result: a creamy, cheesy bake every time.
Drain the sautéed squash thoroughly. You can also pat them with paper towels after straining. Precise pre-baking cleanup is key.
Yes—either before baking (cover tightly and freeze for up to a month) or after baking (cut portions and wrap individually). Thaw in fridge overnight and reheat in a 325°F oven until warmed through.
As written, yes—it’s a richer vegetarian side. To add body, you can stir in cooked veggies or beans.
To reheat, preheat your oven to 325°F and bake uncovered for 15–20 minutes until hot and bubbly. You can also microwave individual slices—about 60–90 seconds on medium power.
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Southern Yellow Squash Casserole
Ingredients
- 6 tablespoons Butter, divided
- 2.5 pounds Yellow squash, sliced 1/4-inch thick
- ½ small Yellow onion, chopped
- 2 teaspoons Kosher salt
- 2 large Eggs
- 8 ounces Sour cream
- 1/2 cup Mayonnaise
- 8 ounces Shredded sharp cheddar cheese
- 4 ounces Shredded Swiss cheese
- 2 sleeves Ritz crackers, crushed
- 1/2 teaspoon Black pepper
Instructions
- Preheat oven to 350°F. Prepare an 11- x 7-inch baking dish by lightly spraying with cooking spray.
- Place 3 tablespoons of butter in a large skillet and heat over medium-high heat. Once melted add the yellow squash, onion and 1 teaspoon of salt and cook for 5-7 minutes until the squash has softened.
- Pour squash and onion mixture into a strainer to remove any excess liquid.
- In a large bowl combine the remaining 1 teaspoon of salt, eggs, sour cream, mayonnaise, 4 ounces of cheddar cheese, 4 ounces of Swiss cheese, black pepper, and 1 cup of crushed Ritz crackers. Stir together. Add the cooked squash and onions and gently toss the mixture together.
- Spoon the mixture into the prepared dish and then sprinkle with the remaining crushed crackers followed by the remaining 4 ounces of shredded cheddar cheese.
- Place in the oven and bake for 20-25 minutes or until the casserole is hot and bubbling and the topping is golden brown.
- Once cooked remove from the oven and let cool for 10 minutes before serving.
