Description

This Butternut Squash Gratin is a rich and creamy Thanksgiving side dish featuring tender roasted butternut squash baked in a luscious Gruyère and Parmesan cheese sauce with fresh sage and thyme. It combines the sweetness of squash with the savory depth of melted cheeses and aromatic herbs, creating delightful comfort food that’s easy to make and perfect for fall or holiday gatherings. The dish is make-ahead friendly and takes less than an hour to prepare and bake.

Ingredients

Butternut Squash

2 ½ pounds butternut squash, cut into 1½-inch pieces
2 tablespoons extra-virgin olive oil (divided)
1 ½ teaspoons kosher salt (divided)

Sauce

4 tablespoons (½ stick) salted butter
2 large shallots, chopped
2 garlic cloves, minced
2 tablespoons chopped fresh sage
2 teaspoons fresh thyme leaves
1 cup heavy cream
¼ teaspoon ground nutmeg
1 ½ cups freshly grated Gruyère cheese
1 cup freshly grated Parmesan cheese

For Serving

Freshly cracked black pepper, to taste
Fresh sage leaves

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Instructions

Preheat the Oven: Preheat your oven to 400°F (200°C) and place the rack in the center position for even baking.
Prepare and Roast the Squash: Arrange the butternut squash pieces in a single layer in an 8 x 8-inch or 7 x 10-inch baking dish. Toss with 1 tablespoon of olive oil and 1 teaspoon of kosher salt until well coated. Bake the squash for 25 minutes to begin roasting and soften.
Make the Cheese Sauce: While the squash roasts, heat the butter along with the remaining 1 tablespoon of olive oil in a large skillet over medium heat. Once melted, add the chopped shallots and cook, stirring occasionally, until tender—about 4 minutes. Stir in the minced garlic, chopped fresh sage, and thyme leaves; cook until fragrant, about 1 minute.
Add Cream and Spices: Pour in the heavy cream, add ground nutmeg, and the remaining ½ teaspoon kosher salt. Stir constantly as the mixture heats until combined and begins to steam, about 5 minutes.
Melt the Cheese: Reduce heat to low and add the Gruyère and Parmesan cheeses. Stir continually until the cheeses melt and the sauce is smooth and creamy, about 5 minutes.
Combine Squash and Sauce: Remove the baking dish from the oven once the squash has roasted for 25 minutes. Pour the warm cheese sauce evenly over the roasted squash.
Bake Until Tender: Return the dish to the oven and bake for an additional 20 minutes, or until the sauce thickens and the squash is tender throughout.
Finish and Serve: Allow the gratin to cool for 5 minutes. Before serving, sprinkle freshly cracked black pepper on top and garnish with fresh sage leaves for added aroma and color.

Notes

Make sure to cut the butternut squash into evenly sized pieces for uniform cooking.
Gruyère and Parmesan give the dish its signature creamy and nutty flavor; freshly grating the cheese ensures better melting and texture.
This gratin can be prepared ahead of time and baked just before serving to save time during holiday meals.
Use fresh herbs for the best flavor, but dried sage and thyme can be substituted in a pinch (use about 1 teaspoon dried each).
For a lighter version, substitute half-and-half for heavy cream, but the sauce will be less rich.

Prep Time: 10 minutes
Cook Time: 45 minutes
Category: Side Dish
Method: Baking
Cuisine: American