Stir in the heavy cream and parmesan cheese and cook for another 1-3 minutes, or until the cheese is melted and the sauce is thick and hot, stirring constantly.
Sauce too thick?
Add a little heavy cream until it thins out.
Sauce too thin?
Make a slurry out of 1 tablespoon of cornstarch and one tablespoon of cold water. Slowly pour it into the sauce and then bring to a boil for one minute.