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Overhead view of baked squash casserole showing a spoonful.
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5 from 2 votes

Summer Squash Casserole

Creamy, cheesy squash casserole with toasted buttery breadcrumbs, a comforting side dish that's perfect for using fresh summer yellow squash.
Prep Time15 minutes
Cook Time45 minutes
Total Time1 hour
Course: Side Dish
Cuisine: American
Servings: 6 servings
Calories: 217kcal

Ingredients

  • tablespoons unsalted butter, divided
  • 1 small onion, finely diced
  • 1 pound yellow summer squash, thinly sliced about 3 medium squash
  • ½ cup grated Monterey Jack cheese
  • 1 egg, lightly beaten
  • ½ cup sour cream
  • 2 tablespoons dry white wine or vermouth
  • ½ teaspoon kosher salt
  • ½ teaspoon sugar
  • Dash or two hot pepper sauce
  • ½ cup fresh bread crumbs
  • 1 tablespoon chopped fresh parsley

Instructions

  • Preheat oven to 350º.
  • Melt 1 tablespoon butter in large skillet over medium-low heat. Add diced onion and cook until translucent, about 5 minutes. Transfer to small bowl and set aside.
  • Add 2 more tablespoons of butter to pan over medium-high heat and add squash. Cook and stir frequently until moisture has evaporated and squash is just tender, about 10 minutes. Transfer to a food processor and pulse until fairly smooth.
  • Transfer processed squash to a large bowl and add onions and all remaining ingredients except bread crumbs and parsley. Mix well and transfer to a small, round buttered baking dish.
  • Melt remaining 1½ tablespoons butter in a small saucepan over medium-high heat. Stir in fresh bread crumbs and cook and stir frequently until golden brown. Sprinkle over squash mixture. Bake for 30 to 35 minutes until hot and bubbly around the edges. Sprinkle with parsley and serve. Enjoy!

Notes

  • Slice the squash thinly and evenly, I use a mandolin to make this task quick and easy.
  • I used white wine but you could also use vermouth.  It’s just a couple tablespoons and it really makes a difference in the flavor profile of this casserole.
  • Freshly grated cheese is best, it tastes and melts better.
  • For fresh bread crumbs, I pulse a piece of French baguette in the food processor until I get some rustic looking crumbs.  Any hearty white bread will work.  Watch carefully so as not to burn when toasting in the butter.
  • Don’t overcook the squash before processing, you just want the moisture cooked out and starting to soften.

Nutrition

Calories: 217kcal | Carbohydrates: 12g | Protein: 6g | Fat: 16g | Saturated Fat: 10g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 4g | Trans Fat: 1g | Cholesterol: 70mg | Sodium: 336mg | Potassium: 284mg | Fiber: 1g | Sugar: 4g | Vitamin A: 701IU | Vitamin C: 15mg | Calcium: 128mg | Iron: 1mg