Creamy Butternut Squash Gratin with Caramelized Onions

Thinly sliced butternut squash is enveloped in a thick creamy sauce of caramelized onions, garlic, and thyme.

Prep Time 20

Cook Time 1

Resting Time 5

Total Time 1 25

Servings servings

Preheat oven to 375°F. Peel butternut squash and cut lengthwise. Remove seeds and pith. Thinly slice crosswise into ⅛-inch thick circles. You can also cut into half-moons.
Melt butter in a large skillet over medium heat. Add sliced onions and season with salt to release juices. Cook until onions are caramelized (approximately 25 minutes), stirring occasionally.
Add garlic, sage leaves, thyme, and season with salt, pepper, and nutmeg and cook just until fragrant.
Reduce heat to medium-low and add heavy cream. Whisk to combine everythingand cook until cream sauce has thickened.
Spoon ¼ of the onion cream mixture to the bottom of the casserole dish. Arrange butternut squash slices across the dish, overlapping slightly. Spoon another ¼ of the cream onion mixture. Add a second layer of the butternut squash, followed by the 3rd ¼ of the onion cream mixture. Add the final layer of butternut squash, overlapping and pressing down so the top is flat all across the baking dish. Drizzle the remaining onion mixture.
Spread the cream onion sauce evenly to cover the squash. Sprinkle with Parmesan cheese and breadcrumbs. Add extra sage leaves on top.
Cover with a piece of parchment paper then aluminum foil. Bake covered for 40 minutes on the middle rack. Remove the cover and broil for the last 5 minutes of cooking time to brown the tops. Remove from oven and allow to rest for 5 minutes for sauce to settle before serving.

The recipe has been slightly modified to exclude arrowroot starch.