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Southern Squash Casserole

Southern squash casserole with tender sliced yellow squash folded into a creamy cheddar custard, then topped with a buttery Ritz cracker crust. Bakes until bubbling, golden, and set in a classic 9x13 dish.
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Prep Time 20 minutes
Cook Time 45 minutes
Total Time 1 hour 5 minutes
Servings: 8 servings
Course: Side Dish
Cuisine: Southern American
Calories: 420
Ingredients Equipment Method Notes

Ingredients
  

Yellow squash casserole base
  • 2 lb yellow squash
  • 1 onion
  • 2 tbsp butter
  • 1 cup shredded sharp cheddar
  • 0.5 cup sour cream
  • 0.25 cup mayonnaise
  • 2 eggs
  • 1 tsp salt
  • 0.5 tsp black pepper
  • 1 sleeve Ritz crackers
  • 3 tbsp butter

Equipment

  • 1 sheet pan
  • 1 Dutch oven

Method
 

Preheat and prepare the dish
  1. Preheat the oven to 350F, then grease a 9x13-inch baking dish.
  2. Slice the yellow squash and dice the onion so they’re ready to cook.
Cook squash and onion
  1. Cook the squash and onion in the 2 tablespoons butter for 10-12 minutes until tender.
  2. Drain the cooked squash mixture well in a colander to prevent a watery casserole.
Mix filling and assemble
  1. Mix the cheddar, sour cream, mayonnaise, eggs, salt, and black pepper until smooth.
  2. Fold the drained squash mixture into the cheese mixture.
  3. Spread the mixture evenly into the prepared baking dish.
Add the topping and bake
  1. Toss the crushed Ritz crackers with the melted butter, then sprinkle evenly over the top.
  2. Bake for 30-35 minutes at 350F until golden and set, with bubbling around the edges.

Notes

For the best texture, drain the squash thoroughly and bake until the center is set (it should not jiggle). Refrigerate leftovers in an airtight container up to 3 days; reheat in a 350F oven until warmed through. Freezing is not recommended because the sour cream and squash can become watery after thawing. For a lighter option, use reduced-fat cheddar and light sour cream while keeping the egg mixture the same.