Bring a large pot of salted water to a rolling boil and add your penne pasta. Cook for 9-11 minutes until al dente, stirring occasionally to prevent sticking. Reserve one cup of pasta water before draining, as this starchy liquid helps adjust sauce consistency later if needed.

While the pasta cooks, melt butter in a large skillet over medium heat and add diced onion. Sauté for 3-4 minutes until the onion becomes translucent and fragrant, then add minced garlic and cook for another minute until the kitchen smells amazing.

Pour in your pumpkin puree and stir constantly for about two minutes to combine with the butter and onions. This step develops the pumpkin flavor and prevents lumps from forming in the sauce base.

Add heavy cream and vegetable broth to the skillet, whisking together until smooth and combined. Sprinkle in Italian seasoning, salt, black pepper, and nutmeg, then stir until every spice distributes evenly throughout the creamy silky pumpkin pasta sauce.

Reduce heat to low and simmer for 5-7 minutes, allowing the sauce to thicken slightly and flavors to meld together beautifully. Add Parmesan cheese and stir until it melts completely into the sauce.

Combine the cooked penne pasta with the sauce in the skillet, tossing until every piece is coated generously. If the sauce seems too thick, add reserved pasta water one tablespoon at a time until you achieve desired consistency.

Remove from heat and stir in fresh chopped sage, reserving a small handful for garnish. Taste and adjust seasonings as needed before serving.