Heat the oil in a skillet over medium heat and saute the onion and garlic until it is soft and translucent. Remove the sausage from casings and add to the pan. Cook until browned.
Deglaze pan with chicken broth. Add Italian seasoning and heavy cream. Let simmer on low for 10 minutes.
Off the heat, slowly stir in parmesan cheese and whisk or stir until melted. Stir in baby spinach. Season with cayenne pepper, salt and pepper to taste. Toss with pasta and serve immediately.