Cook tortelloni according to package directions.
Grill sausage and then slice as preferred. Saute mushrooms in a little olive oil for 3-4 minutes, then then add the spinach and saute until wilted. Season with salt and pepper.
Drain cooked pasta and set aside. In same pot melt butter and then add heavy cream (on low). Add a 2-3 tbslp. of fontina cheese and mix until smooth and creamy. Return pasta to the pot and mix. Add all the ingredients to the pot, mix together and then serve.