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A close-up view of a serving of Southern Squash Casserole on a light ceramic plate, showing tender slices of yellow squash in a creamy cheese sauce topped with golden-brown Ritz cracker crumbs, with a silver fork taking a bite.

Old-Fashioned Southern Squash Casserole

Hilary PARKER
This Southern Squash Casserole is the ultimate comfort food! Featuring tender yellow squash, onions, and a rich, creamy two-cheese sauce, it's topped with a golden, buttery Ritz cracker crust. Perfect for holiday tables or weeknight dinners, this recipe uses a special sauté technique to ensure it is never watery, just perfectly delicious
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Prep Time 20 minutes
Cook Time 30 minutes
Total Time 50 minutes
Course Dinner, Main Dishes
Cuisine American
Servings 8
Calories 385 kcal

Ingredients
  

The Squash Base

  • 3 lbs yellow squash sliced ¼-inch thick (about 5 medium squash)
  • 1 medium yellow onion chopped
  • 3 tbsp unsalted butter
  • 1 tsp salt plus more to taste
  • ½ tsp black pepper

The Creamy Filling

  • 2 large eggs lightly beaten
  • 8 oz sour cream
  • 1 cup sharp Cheddar cheese freshly shredded
  • ½ cup Swiss cheese freshly shredded
  • ½ cup mayonnaise
  • 2 tsp fresh thyme chopped (or ½ tsp dried)

The Cracker Topping

  • 2 sleeves Ritz crackers crushed (about 1½ cups crumbs)
  • 3 tbsp unsalted butter melted
  • ¼ cup Parmesan cheese shredded

Instructions
 

  • Preheat and Prep: Preheat your oven to 350°F (175°C). Lightly grease a 9x13 or 8x8 baking dish with non-stick spray.
  • Sauté the Veggies: In a large skillet over medium-high heat, melt the 3 tablespoons of butter. Add the sliced squash and chopped onion. Season generously with salt and pepper. Cook for 8–10 minutes, stirring occasionally, until the squash is just tender and most of the liquid has evaporated.
  • Drain Thoroughly: Transfer the cooked squash mixture to a colander set over the sink. Let it drain well to remove excess moisture—this is the secret to a non-watery casserole!
  • Make the Sauce: In a large bowl, whisk together the eggs, sour cream, mayonnaise, Cheddar cheese, Swiss cheese, and thyme until creamy and combined.
  • Combine: Gently fold the drained squash and onions into the cheese mixture until everything is evenly coated. Pour the mixture into your prepared baking dish.
  • Add the Crunch: Crush the Ritz crackers (keep them a bit coarse for texture!). In a small bowl, toss the cracker crumbs and Parmesan cheese with the melted butter until coated. Sprinkle evenly over the casserole.
  • Bake: Bake for 20–30 minutes, or until the top is golden brown and the filling is bubbling around the edges.
  • Serve: Let the casserole rest for 5 minutes before serving to help the filling set. Enjoy!

Notes

  • Avoid Pre-Shredded Cheese: For the glossiest, smoothest sauce, grate your own cheese. Pre-bagged cheese has anti-caking agents that can make the sauce grainy.
  • Make Ahead: You can assemble the casserole (without the topping) up to 24 hours in advance. Store covered in the fridge. Add the topping just before baking and add 5-10 minutes to the cook time.
  • Storage: Leftovers can be stored in an airtight container in the refrigerator for up to 3 days.

Nutrition

Calories: 385kcalCarbohydrates: 22gProtein: 10gFat: 29gSaturated Fat: 14gCholesterol: 95mgSodium: 680mgPotassium: 420mgFiber: 2gSugar: 5gVitamin A: 850IUVitamin C: 12mgCalcium: 280mgIron: 1.5mg
Keyword cheesy squash casserole, easy squash casserole, holiday side dish, Ritz cracker topping, Southern squash casserole, vegetable casserole, yellow squash casserole
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