In a large pot, bring salted water to a boil. Add the fettuccine and cook until al dente, about 8-10 minutes. Reserve ½ cup of pasta water before draining.

Heat a skillet over medium heat. Add a tablespoon of butter, let it melt, then add minced garlic and sauté for 1-2 minutes until fragrant.

Lower the heat and add pumpkin puree and heavy cream to the skillet. Stir and heat through for 3-5 minutes until smooth and bubbling.

Gradually whisk in Parmesan cheese until melted and creamy. Use reserved pasta water to adjust the sauce's thickness if needed.

Add drained fettuccine to the sauce and toss to coat evenly. Season with salt and pepper to taste.

Serve in warm bowls, garnished with parsley or sage, and optionally sprinkle with toasted pumpkin seeds.