Best-Ever Yellow Squash Casserole

An overhead view of a large cast-iron skillet filled with a serving of summer squash casserole with a portion of it missing with a serving spoon in the pan.

Best-Ever Yellow Squash Casserole

Course: Side Dish

Cuisine: American, Southern, U.S.

Prep Time: 15

Cook Time: 20

Total Time: 35

Servings: people

Calories: 328kcal

Author: Kris Longwell

Yellow Squash Casserole is a Southern U.S. staple side dish and is cheesy, creamy, and loaded with summer squash taste. And what's even better, the dish is on the table from start to finish in less than 45 minutes!

Print Recipe

Equipment

Mandolin, or sharp knife

Ingredients

cooking spray
1 tablespoon vegetable oil
2½ lbs yellow squash sliced into ¼-inch rounds
1 cup onion chopped
8 oz. sour cream
¼ cup mayonnaise
1½ cups cheddar cheese shredded
½ cup Parmesan cheese grated
1 large egg
1 teaspoon Kosher salt
½ teaspoon freshly ground black pepper
1 sleeve Ritz crackers crushed, but not completely pulverised
2 tablespoon unsalted butter melted

Instructions

Pre-heat oven to 350°F. Lightly spray a 12-inch cast-iron skillet or a 9"x9" casserole dish with cooking spray
cooking spray
In a large skillet, heat the oil over medium-high heat. Add the sliced squash and onion and cook, stirring occasionally, until the vegetables have softened, about 10 minutes. If there is excess liquid, transfer to a colander in the sink to drain.
1 tbsp vegetable oil, 2½ lbs yellow squash, 1 cup onion
In a large mixing bowl, stir together the sour cream, mayonnaise, cheddar cheese, Parmesan cheese, egg, salt, and pepper. Carefully fold in the cooked squash mixture. Transfer to the prepared baking pan or dish.
8 oz. sour cream, ¼ cup mayonnaise, 1½ cups cheddar cheese, ½ cup Parmesan cheese, 1 large egg, 1 tsp Kosher salt, ½ tsp freshly ground black pepper
In a separate medium bowl, use a fork to stir together the crushed crackers with the melted butter. Sprinkle the mixture all over the top of the casserole.
1 sleeve Ritz crackers, 2 tbsp unsalted butter
Bake for 25 minutes, uncovered, until bubbly and the topping is starting to brown slightly. Remove and serve at once.

Video

Notes

NOTE: Watch the video in the recipe card for visual guidance.

Be sure to slice the squash into uniform cuts. ¼-inch slices are a good thickness. A mandolin ensures even slicing, but a sharp knife and a steady hand will work just fine.

Don't over-sauté the squash and onion. Cook until just soft. The vegetables will cook more once the casserole is in the oven.

The casserole can be assembled up to a day in advance and stored in the refrigerator. Allow to come to room temperature before baking (about 1 hour on the counter), or add 10 minutes to the bake time if no time for bringing to room temperature (total bake time will be 35 minutes).

This casserole is best served hot!

Nutrition