Divide squash onto 2 rimmed baking sheets; drizzle each sheet with 1 tablespoon of olive oil, sprinkle with salt and pepper and toss to coat.
Bake for 45–50 minutes or until tender.
Reserve half for penne recipe.
Caramelized Onions
Heat oil in a large skillet over low heat.
Add onions and a pinch of salt. Cook until completely caramelized, stirring occasionally at first and more often as onions begin to brown. Depending on your stove, this could take anywhere from 30 minutes to over an hour.
Season with freshly ground pepper.
Reserve half for penne recipe.
Flatbread
Preheat oven to temperature indicated on pizza crust package.
Top crust with caramelized onions, cheese, and squash.
Bake for time on package or until squash is heated through and cheese has melted.
While pizza is baking, heat oil in small skillet over medium high heat. Add sage leaves and saute, stirring constantly, for about 3 minutes or until leaves are crispy, but still green.
Sprinkle sage leaves and walnuts on pizza before serving.
Notes
Prep and cook time are for flatbread only. If you're making the caramelized onions and butternut squash on the same day you're making the flatbread, allow about an extra hour.
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