In a large deep non stick skillet over medium high heat add one tablespoon of olive oil and brown the sausage. If in casings, remove sausage from casings. Transfer sausage to a paper towel lined plate. Drain fat from skillet and return pan to stove. Add the other tablespoon of olive oil, garlic, and onion. Saute 3 to 5 minutes until onion are tender.
Add bay leaf, sage, and wine to the pan. Reduce wine by half, about 2 minutes. Add stock and pumpkin and stir to combine, stirring sauce until it comes to a bubble. Return sausage to pan, reduce heat, and stir in cream. Season the sauce with the cinnamon and nutmeg. Add salt and pepper to taste. Simmer mixture 5 to 10 minutes to thicken the sauce.
Return drained pasta to the pot it was cooked in. Remove the bay leaf from the sauce and pour the pumpkin sauce over pasta. Combine pasta and sauce and toss over low heat for about 1 minute. Garnish the pasta with shaved cheese and sage leaves.
