Buttercream Frosting
from Half Assed Kitchen

1-1/2 cups butter or margarine, room temperature
4-5 cups sifted powdered sugar
2 Tablespoons milk (can also substitute soy or rice milk)
1 teaspoon vanilla extract

Cream together butter and sugar with a mixer. Then add milk–in small increments–and vanilla. 

You can play around with the proportions. For instance, when we use a pastry bag, we try to make our frosting extra-stiff. (Yes, we did just type that.) So we are liberal with our powdered sugar.

Beat until smooth and creamy.

If desired, add a few drops of food coloring and mix thoroughly.