Go Back
Butternut Squash Casserole

Butternut Squash Casserole - Cozy, Comforting, and Easy

Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Servings 4 servings

Ingredients
  

  • 1 large butternut squash (about 3 pounds), peeled, seeded, and cubed
  • 2 tablespoons olive oil
  • 1 medium yellow onion, finely chopped
  • 2 cloves garlic, minced
  • 2 tablespoons unsalted butter (or more olive oil)
  • 1/2 cup whole milk or half-and-half
  • 1/2 cup sour cream or plain Greek yogurt
  • 1 large egg, lightly beaten
  • 3/4 cup grated Parmesan, divided
  • 1/2 cup shredded sharp cheddar or Gruyère
  • 1 teaspoon kosher salt, plus more to taste
  • 1/2 teaspoon black pepper
  • 1 teaspoon fresh thyme leaves (or 1/2 teaspoon dried)
  • 1/4 teaspoon ground nutmeg (optional but recommended)
  • For the topping: 1 cup panko or fresh breadcrumbs, 2 tablespoons melted butter, 2 tablespoons chopped parsley, pinch of salt

Instructions
 

  • Prep the oven and pan: Heat the oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish or similar casserole dish.
  • Cook the squash: Place cubed squash on a baking sheet. Drizzle with 1 tablespoon olive oil, season with a pinch of salt and pepper, and toss. Roast for 25–30 minutes, stirring once, until very tender and lightly caramelized on the edges.
  • Sauté the aromatics: While the squash roasts, warm the remaining 1 tablespoon olive oil and 2 tablespoons butter in a skillet over medium heat. Add chopped onion and a pinch of salt. Cook 6–8 minutes, stirring often, until soft and translucent. Stir in garlic and cook 30 seconds until fragrant. Remove from heat.
  • Mash the squash: Transfer roasted squash to a large bowl. Mash with a potato masher or fork until mostly smooth, leaving a few small chunks for texture. You can also use a food processor for a silkier puree.
  • Build the filling: Stir in the sautéed onions and garlic, milk, sour cream, beaten egg, 1/2 cup Parmesan, cheddar or Gruyère, thyme, nutmeg, 1 teaspoon salt, and black pepper. Taste and adjust seasoning. The mixture should be creamy but not soupy.
  • Make the topping: In a small bowl, toss panko with melted butter, remaining 1/4 cup Parmesan, parsley, and a pinch of salt until evenly coated.
  • Assemble: Spread the squash mixture into the prepared baking dish. Sprinkle the breadcrumb topping evenly over the surface.
  • Bake: Place the casserole in the oven and bake for 20–25 minutes, until the topping is golden and the edges bubble slightly.
  • Rest and serve: Let it rest for 10 minutes so it sets up. Scoop and serve warm.