1 cup (2 sticks) of unsalted butter
6 to 8 cups of powder sugar
1/2 cup of milk
1 teaspoon of pure vanilla extract
In electric mixer cream butter until smooth and creamy. With mixer at low speed add 6 cups of powdered sugar, milk, and vanilla; mix until light and fluffy. If neccessary, gradually add remaining 2 cups to reach desired consistency.