Sheet Pan Squash Casserole
A cheesy, crowd-pleasing squash casserole baked on a sheet pan for crispy edges in every bite. Layers of butter crackers, melted cheddar, and tender squash create the perfect potluck dish.
Ingredients
- For the Casserole:
- 2 lbs summer squash yellow squash or zucchini, sliced ¼-inch thick
- 5 cups water
- ½ medium yellow onion chopped
- 1¾ teaspoons salt divided
- 1 sleeve butter crackers for base layer
- 4½ cups cheddar cheese grated and divided
- ⅔ cup sour cream
- ⅔ cup mayonnaise
- ¼ cup heavy whipping cream
- ½ teaspoon garlic powder
- ¼ teaspoon black pepper
- 2 large eggs beaten
- For the Topping:
- 1 cup butter crackers crushed
- 1 tablespoon unsalted butter melted
Instructions
- Preheat oven: Preheat oven to 350°F. Spray a 10×15-inch rimmed baking sheet with nonstick spray.
- Cook the squash: In a large pot, combine sliced squash, chopped onion, 5 cups water, and 1 teaspoon salt. Bring to a boil over high heat, then reduce to a simmer. Cook for 7 minutes until squash is tender. Drain well in a colander and let excess water drip out for 2 minutes.
- Create the base layer: Line the bottom of the prepared sheet pan with the sleeve of butter crackers. Sprinkle 3½ cups of shredded cheddar evenly over the crackers. Bake for 5 minutes to melt the cheese.
- Make the creamy filling: In a medium bowl, whisk together sour cream, mayonnaise, heavy cream, garlic powder, black pepper, remaining ¾ teaspoon salt, and beaten eggs until well combined.
- Layer the squash: Remove pan from oven. Spread the drained squash and onions evenly over the melted cheese-cracker base. Pour the creamy egg mixture slowly over the squash in a spiral pattern, nudging it into any dry spots.
- Add toppings: Sprinkle the remaining 1 cup of cheddar cheese over the squash. In a small bowl, mix crushed crackers with melted butter until coated. Scatter the buttered cracker crumbs over the top in a loose layer.
- Bake: Bake for 25 minutes until the center is set (not jiggly) and the top is golden brown. Start checking at 20 minutes as ovens vary.
- Rest before serving: Let the casserole rest for at least 20 minutes before cutting to allow it to firm up for clean slices.
Notes
Storage: Cover tightly and refrigerate for up to 4 days. Flavors improve on day two.
Reheating: For best results, reheat individual portions in the oven at 300°F for 10-12 minutes to maintain crispy topping. Microwave for 1-2 minutes if needed, though crackers will soften.
Make-Ahead: Prepare up to the point of baking, cover tightly, and refrigerate for up to 24 hours. Let sit at room temperature for 20 minutes before baking, adding 5 extra minutes to baking time.
Substitutions: Use zucchini or a mix of both squashes. For gluten-free, use substitute crackers. Greek yogurt can replace sour cream for a lighter version.
Pan Size: A 9×13-inch casserole dish works fine but will be thicker. Add 5-10 minutes to baking time.
Avoiding Watery Casserole: Ensure squash is well-drained after boiling. Press gently with paper towels if very wet. Don't skip the 20-minute cooling time.Claude can make mistakes. Please double-check responses.
Reheating: For best results, reheat individual portions in the oven at 300°F for 10-12 minutes to maintain crispy topping. Microwave for 1-2 minutes if needed, though crackers will soften.
Make-Ahead: Prepare up to the point of baking, cover tightly, and refrigerate for up to 24 hours. Let sit at room temperature for 20 minutes before baking, adding 5 extra minutes to baking time.
Substitutions: Use zucchini or a mix of both squashes. For gluten-free, use substitute crackers. Greek yogurt can replace sour cream for a lighter version.
Pan Size: A 9×13-inch casserole dish works fine but will be thicker. Add 5-10 minutes to baking time.
Avoiding Watery Casserole: Ensure squash is well-drained after boiling. Press gently with paper towels if very wet. Don't skip the 20-minute cooling time.Claude can make mistakes. Please double-check responses.