Cook the pasta according to package instructions until al dente.
Heat olive oil in a large skillet over medium heat.
Add minced garlic and sauté for 1-2 minutes until fragrant.
Stir in the pumpkin puree and mix well.
Pour in the heavy cream and bring to a gentle simmer.
Add grated Parmesan cheese, sage, nutmeg, salt, and pepper.
Stir until the cheese melts and the sauce is smooth.
Drain the pasta and reserve a bit of pasta water.
Combine the pasta with the pumpkin sauce, adding reserved water as needed for consistency.
Serve hot, garnished with pumpkin seeds.