Heat oven to 400 F. Brush the squash with 1 tablespoon oil and season generously with pepper. Roast about 60 minutes or until soft. Remove from oven and let cool to room temperature.
Bring a large pot of water to a boil. Add the pasta and cook according to package instructions.
Place cooked butternut squash in large food processor or blender. Puree until smooth. Slowly add the broth and puree until the sauce reaches the desired consistency. You may need to add a little water, depending on the size of your squash.
In a small skillet, heat the remaining olive oil over medium-high heat until shimmering slightly. Add the sage and cook until bright green, about 30 seconds. Add the onion, red pepper and garlic. Saute until soft, 3 to 5 minutes. Add the pureed butternut squash. Season with vinegar, nutmeg and more black pepper. Add the pasta and stir until pasta is well-coated. Sprinkle with Parmesan cheese, if desired. Serve.