1. Cook the pasta: Bring a large pot of salted water to a rolling boil. Add your chosen pasta and cook according to package directions until al dente. Before draining, reserve about 1 cup of the starchy pasta water. Drain the pasta and set it aside.

2. Saute aromatics: While the pasta is cooking, melt the butter in a large skillet or Dutch oven over medium heat. Add the finely chopped onion and cook until it softens and becomes translucent, about 3-5 minutes.

3. Add the garlic and spices: Stir in the minced garlic, dried sage, and nutmeg. Cook for another minute until the garlic is fragrant. Be careful not to burn the garlic.

4. Whisk in the pumpkin and liquids: Pour in the canned pumpkin puree, heavy cream, and milk. Whisk everything together until the mixture is smooth and well combined. Bring the sauce to a gentle simmer, stirring occasionally. Do not let it boil vigorously.

5. Stir in the cheese: Reduce the heat to low and gradually stir in the grated Parmesan cheese until it’s fully melted and the sauce is smooth and creamy. Season the sauce with salt and black pepper to taste.

6. Combine pasta and sauce: Add the drained pasta directly into the skillet with the pumpkin alfredo sauce. Toss gently to coat all the pasta evenly. If the sauce seems too thick, add a splash or two of the reserved pasta water until it reaches your desired consistency.

7. Serve immediately: Garnish with fresh chopped parsley and extra grated Parmesan cheese, if desired. Serve hot and enjoy!