Heat 1/4 cup of olive oil in a large skillet over medium heat. Add 1 finely chopped onion, cooking for 5-7 minutes until it turns translucent and fragrant.

Stir in 2 minced garlic cloves and 1/4 cup of chopped fresh sage, cooking for about 1 minute more.

Mix in a 15-ounce can of pumpkin puree, stirring well for 2-3 minutes until heated through.

Pour in 1/2 cup of heavy cream and add 1/4 cup of grated Parmesan, stirring until smooth. Season with salt, black pepper, and 1/4 teaspoon of red pepper flakes.

Reduce heat to low and let the sauce simmer for 10-15 minutes, adding up to 1/2 cup of vegetable broth or reserved pasta water if it thickens too much.

While sauce simmers, bring a large pot of salted water to a boil. Cook 1 pound of pasta until al dente, reserving 1/2 cup of pasta water before draining.

Add the drained pasta directly to the skillet with the creamy pumpkin sauce, tossing to combine. Adjust thickness with reserved pasta water as needed.

Drizzle 2 tablespoons of melted butter over the pasta and stir gently. Serve hot, garnished with remaining crumbled feta and 1/4 cup of toasted pumpkin seeds.