Preheat oven to 375 degrees. Butter 9x13 pan.

Cook sausage in large skillet over medium heat for about 8 minutes, until fat is rendered. Remove from skillet with a slotted spoon, drain on paper towels and set aside. Discard fat from the skillet, leaving no more than 2 tablespoons.

Add onion, garlic, cayenne pepper and oil to the skillet. Cook, stirring occasionally until soft. Stir in pumpkin puree, chicken stock and sage. Mix together and add salt. Bring to a boil then lower the heat and simmer 5 minutes. Stir in cream and sausage. Simmer until the sauce comes together and is thickened slightly.

Add cooked pasta and parsley to the skillet and gently toss all the ingredients together. Spoon into prepared pan. Sprinkle the top with Parmesan cheese and bake for 35 minutes until topping is golden brown.