Bring a large pot of salted water to a rolling boil over high heat. Add the fettuccine and cook until al dente, about 8-10 minutes. Reserve 1 cup of pasta water and drain.

Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add the chopped onion and sauté for 5-6 minutes until softened and translucent.

Add the minced garlic and cook for 1 minute, allowing the garlic to become fragrant.

Mix in the pumpkin puree and heavy cream, stirring continuously until combined and smooth. Warm for 2-3 minutes.

Gradually add grated Parmesan cheese and nutmeg, stirring until the cheese melts and the sauce thickens about 2-3 minutes.

Taste the sauce, adding salt and black pepper to preference. If too thick, stir in reserved pasta water to reach desired consistency.

Toss the cooked fettuccine in the pumpkin sauce, cooking for another minute over low heat. Garnish with fresh sage leaves.