Cheesy Butternut Squash Casserole with Kale, Walnut-Crust Topping Recipe
This Cheesy Butternut Squash Casserole features creamy roasted butternut squash and sautéed kale in a rich cheesy filling, topped with a crispy Parmesan and walnut sourdough crust. Perfectly balancing sweet, savory, and crunchy textures, this dish is an elegant and nutritious holiday side or comforting vegetarian main.
- Prep Time: 20 minutes
- Cook Time: 50 minutes
- Total Time: 1 hour 10 minutes
- Yield: 6 servings 1x
- Category: Side Dish
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
Ingredients
Scale
Casserole Filling
- 1 (2.5 lb.) butternut squash, peeled and cubed (about 2 lbs. cubed)
- 1 medium yellow onion, diced
- 5 cloves garlic, minced
- 1 bunch kale, stems removed and leaves chopped
- 1 cup heavy cream
- 1/3 cup grated Parmesan cheese (plus 2 Tbsp. reserved for topping)
- Fresh thyme, 1 tsp. leaves
- 1 tsp. Dijon mustard
- Salt and black pepper, to taste
- 1/4 tsp. red pepper flakes
- 2 Tbsp. olive oil
- 1 cup shredded Gruyere cheese
Topping
- 1 cup torn sourdough bread (or panko breadcrumbs)
- 1/2 cup chopped walnuts
- 2 Tbsp. grated Parmesan cheese
- 1 Tbsp. olive oil
Instructions
- Preheat and Sauté Aromatics: Preheat your oven to 425ºF. Heat 2 tablespoons of olive oil in a large sauté pan over medium heat. Add the diced onion and cook for 7 to 8 minutes until softened and translucent. Stir in the minced garlic and red pepper flakes and cook for an additional 2 minutes until fragrant.
- Cook Kale and Add Cream: Add the chopped kale to the pan and sauté until it softens, about 3 to 4 minutes. Pour in 1 cup of heavy cream, then stir in 1/3 cup of Parmesan cheese, fresh thyme leaves, Dijon mustard, salt, and pepper. Let the mixture simmer gently until it slightly thickens, about 5 minutes.
- Assemble Casserole: In a greased baking dish, evenly arrange the cubed butternut squash. Pour the creamy kale mixture over the squash, stirring gently to distribute it well through the squash. Scatter the shredded Gruyere cheese evenly on top. Cover the casserole loosely with aluminum foil.
- Bake First Phase: Bake the casserole at 425ºF for 30 minutes, allowing the squash to cook through and the filling to meld.
- Prepare Topping: While baking, combine torn sourdough bread, chopped walnuts, remaining 2 tablespoons Parmesan cheese, and 1 tablespoon olive oil in a medium bowl. Massage the oil into the bread mixture until well-coated.
- Add Topping and Continue Baking: Remove the casserole from the oven and discard the foil. Evenly scatter the sourdough and walnut topping over the casserole. Return the dish to the oven and bake for another 15 minutes until the squash is tender and the filling thickens.
- Broil for Crust: For a beautifully browned crust, broil the casserole for 1 to 2 minutes at the end of baking if desired. Watch closely to prevent burning.
Notes
- To make this casserole a main dish, stir in browned Italian or chicken sausage before baking.
- You can prepare cubed butternut squash up to 3 days in advance and kale up to 1 day ahead; store separately refrigerated.
- Leftover casserole keeps refrigerated in an airtight container for up to 5 days.
- Reheat leftovers in a 350ºF oven for best texture; microwave reheating is possible but less crisp.
- Freeze casserole in a freezer-safe container for up to 3 months; thaw overnight and reheat in the oven.
- Use a sharp chef’s knife and durable peeler for easier butternut squash prep; cutting into 1-inch cubes ensures even cooking.
Keywords: butternut squash casserole, cheesy casserole, holiday side dish, kale casserole, Parmesan crust, walnut topping, vegetarian casserole, fall recipe