Bring a large pot of salted water to a boil. Cook the fettuccine according to package instructions until al dente. Reserve 1 cup of pasta water, then drain the pasta and set aside.

In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant, being careful not to burn it.

Stir in the pumpkin puree, heavy cream, dried sage, and nutmeg. Cook for about 2-3 minutes, stirring occasionally, until the mixture is heated through.

Add the grated Parmesan cheese to the pumpkin mixture, stirring until it melts and the sauce becomes creamy. If the sauce is too thick, gradually add reserved pasta water until you reach your desired consistency.

Season the sauce with salt and pepper to taste. Add the cooked pasta to the skillet, tossing to coat it evenly in the creamy sauce.

Serve immediately, garnished with fresh parsley and additional Parmesan cheese if desired.