Melt the butter in a medium-sized saucepan over medium heat. Add cream cheese and garlic powder, stirring with a wire whisk until smooth.
Add milk a little at a time while, continue to whisk.
Stir in Parmesan cheese and salt & pepper. Remove from heat when it gets to the desired consistency. The sauce will thicken rapidly, thin with milk if needed.
Serve over fettuccine or linguini noodles and garnish with fresh parsley.
