Scalloped Sweet Potatoes and Butternut Squash

Step 1
Preheat the oven to 350 degrees F (175 degrees C). Grease an 8×8-inch baking dish.

Step 2
Brush sweet potatoes and squash with olive oil. Arrange sweet potatoes on a baking sheet; set squash aside.

Step 3
Bake sweet potatoes in the preheated oven for 5 minutes. Add squash to sweet potatoes; cook until almost tender, 10 to 15 minutes. Remove and cool.

Step 4
Heat butter in a saucepan over medium heat; cook and stir onion in butter until tender, about 10 minutes. Add milk, flour, and sage; season with garlic salt and black pepper. Cook and stir until flour is dissolved and sauce is thickened, 5 to 10 minutes.

Step 5
Remove and discard skins from sweet potatoes and squash. Thinly slice sweet potatoes and squash. Arrange sweet potato slices in the bottom of the prepared baking dish. Layer 1/2 of the squash atop sweet potatoes. Pour a little less than 1/2 of the cream sauce over squash. Sprinkle with 1/2 of the Asiago cheese. Repeat layering with remaining squash, cream sauce, and Asiago cheese, respectively. Cover the dish with aluminum foil.

Step 6
Bake in the preheated oven for 25 minutes. Remove foil and bake until cheese is melted and bubbling, about 10 more minutes.