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. Sauce will thicken rapidly, thin with milk if needed.
Serve over fettuccine or linguini noodles and garnish with fresh parsley.