Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add 1 chopped onion and sauté for 5-7 minutes until it becomes translucent and fragrant.

Once the onion is tender, stir in 2 minced garlic cloves and 1 tablespoon of chopped fresh sage. Cook for about 1 minute until the garlic is fragrant.

Add 1 cup of pumpkin puree to the skillet, stirring to combine with the onion, garlic, and sage. Cook for 2-3 minutes, stirring frequently.

Pour in 1 cup of heavy cream and add 1/2 cup of grated Parmesan cheese. Stir until the cheese melts completely and the sauce is smooth.

Season the sauce with salt, pepper, and optional red pepper flakes, to taste. Simmer on low heat for 10-15 minutes, stirring occasionally.

While the sauce simmers, bring a large pot of salted water to a boil. Cook your pasta according to package instructions until al dente.

Add the drained pasta to the skillet with the pumpkin sauce. Toss everything together gently over low heat.

Sprinkle in half of the crumbled feta cheese and fold it into the pasta gently. Allow it to warm through.

Drizzle melted butter over the pasta for added richness. Garnish with the remaining feta and pumpkin seeds.