Preheat oven to 400℉. Line a baking sheet with parchment, place the butternut squash throughout the pan and drizzle with olive oil (about 1 tablespoon) and coat. Bake for about 10 minutes.
Prep the onions, peppers and garlic into a medium bowl and drizzle with olive oil, about 1/2 tablespoon. Then arrange these vegetables throughout the pan with the squash. Bake for another 30 minutes until they are tender and golden.
Meanwhile, over medium-high heat, boil water in a large sauce pot, then add pasta and follow the package instructions until the pasta is al dente. Drain and reserve 1/2 cup of the pasta water.
Once the roasted squash, peppers, onions and garlic are cooked, add to the food processor, drizzle in 2 tablespoons of olive oil while pulsing. You get a thick sauce and small chunks of squash.
Over medium heat, add 1 tablespoon of olive oil to a large skillet, cook the sage for about 3-4 minutes, then add the processed squash with the 1/2 cup of reserve pasta water, stirring until smooth. Add the cooked pasta and gently stir and fold the pasta until coated with the sauce and cook for another 1-2 minutes to heat through.
Serve immediately and garnish with parmesan cheese.
