Preheat the oven to 400°F (200°C). Toss the cubed butternut squash with 1 tablespoon of olive oil, salt, and pepper. Spread on a baking sheet and roast for 25-30 minutes until tender.

In a pot, heat the remaining tablespoon of olive oil over medium heat. Add the chopped onion and garlic, and sauté until translucent.

Add the roasted butternut squash and vegetable broth to the pot. Bring to a simmer and cook for 5 minutes.

Use a blender to puree the sauce until smooth. Return to the pot and stir in nutmeg and parmesan cheese if using. Adjust seasoning to taste.

Cook the pasta according to package instructions. Drain and reserve some pasta water.

Toss the cooked pasta with the butternut squash sauce, adding reserved pasta water as needed to reach desired consistency.

Serve warm, garnished with additional parmesan cheese and freshly cracked black pepper.