Winter Gruyere Gratin

 

Butter

1 large butternut or kabocha squash

2 shallots, chopped

2 cups (8 ounces) shredded Gruyère cheese, divided

2 cups heavy whipping cream

1 tsp. Dijon mustard

2 tsp. chopped fresh sage

1 tsp. salt

¾ tsp. freshly ground black pepper

Pinch of crushed red pepper flakes

 

Preheat oven to 375°. Butter a 13×9-inch baking dish. Peel squash and cut in half; remove seeds and discard. Cut squash halves into ⅛-inch slices. Arrange half of squash pieces on bottom of baking dish. Sprinkle with shallots and 1 cup cheese. Top with remaining squash slices and remaining 1 cup cheese. Whisk together cream, mustard, sage, salt, pepper, and red pepper flakes in a small bowl. Pour over squash slices. Cover with aluminum foil and bake 1 hour or until squash is tender and almost done. Uncover and bake 10 to 15 minutes or until golden brown and bubby.