Bring a large pot of salted water to a boil. Add the pasta and cook until al dente, following package directions. Before draining, reserve 1 cup of pasta water. Drain the pasta and set it aside.

While the pasta cooks, melt the butter in a large saucepan over medium heat. Add the flour and whisk until the mixture turns golden and smells nutty. Stir in the minced garlic and cook for about 30 seconds.

Pour in the milk a few splashes at a time, whisking after each addition to keep the mixture smooth. Raise the heat to medium-high and keep stirring. Cook for 8 to 10 minutes until the sauce bubbles and thickens.

Take the saucepan off the heat. Stir in the pumpkin puree, cream cheese, half of the chopped sage, salt, black pepper, cinnamon, nutmeg, and cayenne. Whisk until smooth, then taste and adjust the seasoning as you like.

Add the cooked pasta to the saucepan and toss gently until the noodles are coated. If the sauce seems too thick, stir in reserved pasta water a little at a time until it reaches the texture you prefer.

Divide the pasta among serving bowls. Top each portion with Parmesan and the remaining sage. Serve right away while the sauce is warm and creamy.

For leftover pasta, add a splash of milk before reheating gently in the microwave. Stir partway through heating, then add more milk if the pasta needs extra moisture.