Cook the pasta in a large pot of boiling water according to package instructions. Drain and reserve ¾ cup of the pasta water. Set aside.
While pasta cooks, add 1 tablespoon olive oil to a large skillet over medium heat. Once hot, cook the garlic for 1 - 2 minutes, until fragrant.
Turn the heat to medium low and add the cream cheese. Once it begins to soften, stir in the milk. Stir and mash the milk and cream cheese together until it is melted and no lumps remain. Turn up the heat if needed to melt the cream cheese.
Stir in the pumpkin puree, sage, nutmeg, cinnamon, salt and pepper, to taste (I usually add ½ teaspoon salt and ¼ teaspoon pepper).
Stir in the parmesan cheese until melted.
Stir the pasta and pasta water gently into the sauce until combined. If desired, add less than the full ¾ cup pasta water for a thicker sauce.
Serve immediately, optionally topped with more parmesan cheese.