Prepare Roasted Butternut Squash: Preheat oven to 400 degrees F. Arrange squash onto a rimmed baking sheet; drizzle with 1 tablespoon olive oil, sprinkle with salt and pepper, and toss to coat. Bake for 45-50 minutes or until tender.
Prepare Caramelized Onions: Heat 1 tablespoon olive oil in a large skillet over low heat. Add onions and a pinch of salt. Cook until completely caramelized, stirring occasionally; about 30-45 minutes. Season with freshly ground pepper.
Prepare Flatbread: Cut one sheet of 6 rolls in half horizontally. Gently flatten both halves with a rolling pin and transfer, cut-side-up, to a prepared baking sheet. Brush rolls with a bit of olive oil, then top with caramelized onions, cheese, and roasted squash. Bake for 5-6 minutes at 400 degrees F or until cheese is melted and flatbread is heated through.
Meanwhile, heat remaining 1 tablespoon olive oil in small skillet over medium-high heat. Add sage leaves and sauté, stirring constantly, for about 3 minutes or until leaves are crispy, but still green. Sprinkle sage leaves and walnuts on flatbread before serving.
Recipe adapted from: www.ohmyveggies.com