Creamy, rich, delectable. Hands down the best alfredo sauce I've ever made.
Melt butter in saucepan. When melted, add sour cream and soften.
Stir in heavy cream. Add garlic powder, a touch of salt, and a few grinds of pepper.
Simmer gently for 15 minutes. Remove from heat and fold in parmesan.
Mix with hot fettuccine and serve.