In a saucepan, combine the butter and heavy cream. Simmer until all is melted and mixed well. Stir in the Parmesan cheese and garlic powder. Simmer for 15 to 20 minutes on low. You may wish to add a little salt and pepper.
Additional Notes
I have made this with half-and-half, but we prefer the heavy cream. I wouldn’t recommend trying it with plain milk.
Important: DO NOT use store-bought shredded or grated cheese. Preshredded and pregrated cheeses have an anticaking agent in them that can prevent the sauce from setting up.