This Butternut Squash Gratin is the ultimate comfort food, perfect for special occasions like Thanksgiving or Christmas. Creamy and savory with a touch of sweetness from the squash, it’s topped with a golden, crispy breadcrumb crust that everyone will love. A blend of gruyère, parmesan, and pecans makes this dish indulgent yet balanced. Whether as a holiday side or a hearty dish for any gathering, this gratin is sure to be the star of the table.

Butternut Squash Gratin

Why You’ll Love This Recipe

This Butternut Squash Gratin is an irresistible combination of creamy, cheesy goodness and crunchy texture. The subtle sweetness of the butternut squash pairs perfectly with the savory flavors of the leeks, fennel (optional), and garlic. The rich, nutmeg-infused cream ties it all together, and the golden, crispy topping of breadcrumbs and cheese adds a satisfying crunch. Whether you’re preparing for a holiday feast or a special dinner, this gratin brings warmth and elegance to any meal, making it a crowd-pleaser that’s easy to prepare and guaranteed to impress.

Ingredients

For the gratin
3 tablespoons butter, divided (or use all oil if you prefer)
3 tablespoons olive oil, divided
2 large leeks, white and light green parts, cleaned of all dirt and thinly sliced
1 small fennel bulb, stalks removed, halved and cored, and sliced 1/4-inch thick (optional)
Kosher salt and freshly ground black pepper
2 cloves garlic, minced
1 cup heavy cream
1/2 teaspoon nutmeg
2 1/2 pounds butternut squash, peeled, and thinly sliced (about 1/8 inch thick) see photos in post for guidance
1 cup grated gruyère cheese, divided (about 3 ounces)
2 cups coarse fresh breadcrumbs or panko
1/4 cup parmesan cheese
1/3 cup pecans (optional)
2 tablespoons chopped chives, optional for garnish

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

Directions

Preheat the oven to 375ºF (190ºC). Grease a 8-½ × 11-½-inch oval or rectangular shallow baking dish with 1 tablespoon butter (or oil).
In a large skillet, heat 1 tablespoon butter and 1 tablespoon olive oil over medium heat. Add the leeks and fennel (if using), season with 1 teaspoon salt and a few pinches of black pepper, and sauté, tossing occasionally, until softened and lightly browned, about 8 minutes. Add the minced garlic and cook for 1 more minute.
In a large mixing bowl, combine the heavy cream, nutmeg, 1/4 teaspoon salt, and 1/4 teaspoon black pepper. Add all the butternut squash slices, 3/4 cup of gruyère cheese, and the leek mixture. Toss everything together until well combined, then transfer to the prepared baking dish. Press down gently on the top to ensure everything is laying as flat as possible.
In a medium bowl, combine the remaining 1/4 cup gruyère cheese, breadcrumbs, parmesan cheese, and pecans (if using). Evenly spread this mixture over the top of the squash. Dot with the remaining tablespoon of butter, cut into small pieces.
Cover the dish tightly with aluminum foil and bake for 30-40 minutes, or until the squash is tender when pierced with a fork.
Remove the foil and bake for an additional 10-15 minutes, or until the top is golden brown and the gratin is bubbling.
Let the gratin cool for at least 15 minutes before garnishing with chives, if using. Slice and serve.

Servings and timing

This recipe serves 8.

Prep time: 25 minutes
Cook time: 45 minutes
Total time: 1 hour 10 minutes

Variations

Add more vegetables: Feel free to add extra veggies like sweet potatoes, carrots, or parsnips to the gratin for a variety of flavors and textures.
Herb variations: You can swap the chives for other fresh herbs like thyme, rosemary, or sage, depending on your taste preferences.
Cheese swap: For a different cheesy flavor, try using cheddar, fontina, or a mix of cheeses.
Make it vegan: To make this gratin vegan, substitute the heavy cream with coconut cream or a plant-based cream, and use a dairy-free cheese substitute.

Storage/reheating

Leftovers can be stored in an airtight container in the refrigerator for up to 4 days. To reheat, cover the gratin with foil and bake at 350ºF (175ºC) until warmed through. If it seems dry, add a splash of cream before reheating.

FAQs

Can I prepare this gratin ahead of time?

Yes, you can assemble the gratin up to a day in advance. Cover it tightly and store it in the refrigerator. When ready to bake, allow it to come to room temperature for 15 minutes before baking as directed.

Can I use pre-sliced butternut squash?

Yes, pre-sliced butternut squash can be used for convenience. Just ensure the slices are about 1/8 inch thick for even cooking.

What’s the best way to slice butternut squash?

To slice butternut squash, peel it first, then cut off the top and bottom. Cut the squash in half lengthwise, scoop out the seeds, and slice the flesh into 1/8-inch thick rounds. A sharp knife or mandoline slicer will make this easier.

How do I know when the gratin is done?

The gratin is done when the squash is tender when pierced with a fork, and the top is golden brown and bubbling. If the top isn’t as crispy as you like, you can broil it for an additional 1-2 minutes.

Can I freeze the gratin?

Freezing this gratin is not recommended, as the texture of the squash and cream may change once thawed. However, you can store leftovers in the refrigerator for a few days.

Can I use a different type of cheese?

Absolutely! While gruyère and parmesan work beautifully in this recipe, you can use other cheeses like cheddar, fontina, or even a mix of cheeses for a different flavor profile.

Is the fennel necessary for this recipe?

No, fennel is optional. If you like its mild anise flavor, it adds a nice touch, but the gratin is delicious without it.

Can I make this gratin without breadcrumbs?

Yes, you can omit the breadcrumbs or substitute them with crushed nuts (like pecans or almonds) for a different texture.

Can I use non-dairy cream in this recipe?

Yes, you can substitute the heavy cream with a non-dairy alternative like coconut cream or a plant-based cream to make it dairy-free.

How do I store the leftovers?

Store leftover gratin in an airtight container in the refrigerator for up to 4 days. Reheat in the oven or microwave before serving.

Conclusion

This Butternut Squash Gratin is the perfect side dish for any holiday meal or special occasion. With its creamy, cheesy filling, crisp breadcrumb topping, and the sweet, earthy flavor of roasted squash, it’s guaranteed to be a hit at your next gathering. Whether you’re serving it for Thanksgiving, Christmas, or a cozy dinner, this gratin is sure to impress and satisfy everyone at the table.