Bring a large pot of salted water to a boil.
Add farfalle pasta and cook until al dente. Reserve 1/2 cup pasta water before draining.
In a separate pan, sauté chopped onion and minced garlic until fragrant.
Add diced pumpkin and cook until tender.
Transfer cooked pumpkin mixture to a blender.
Add vegetable broth, heavy cream, nutmeg, sage, salt, and pepper. Blend until smooth.
Return blended sauce to pan, warm over low heat.
Gradually add grated Parmesan cheese, stirring until melted.
If sauce is thick, add reserved pasta water to adjust consistency.
Add cooked pasta to sauce, toss to coat evenly.
Garnish with extra Parmesan and chopped parsley.
Serve in bowls and enjoy!