In a large skillet, heat ¼ cup of olive oil over medium heat. Add the chopped onion and sauté until translucent, about 5-7 minutes.

Stir in minced garlic and chopped fresh sage. Sauté for another minute until fragrant.

Add the pumpkin puree, stirring well and cook for 2-3 minutes until heated through.

Pour in the heavy cream and add grated Parmesan cheese. Stir until smooth and the cheese has melted.

Season the sauce with salt, black pepper, and red pepper flakes. Mix well.

Reduce heat to low and let the sauce simmer for 10-15 minutes, adjusting thickness with broth or pasta water as needed.

In a large pot, bring salted water to a boil. Cook the pasta according to package instructions until al dente.

Add the drained pasta directly into the skillet with the sauce and toss to coat.

Fold in half of the crumbled feta cheese.

Drizzle melted butter over the pasta and toss to blend.

Serve immediately, garnished with remaining feta and toasted pumpkin seeds.