Beat 1/2 lb. unsalted unsalted butter until fluffy.
Add and beat in 1 1/2 lb. confectioner's sugar.
3 T. milk
1-2 T. pure vanilla
Variations: substitute some milk with orange juice and rind
omit 1 T. of milk and vanilla and substitute Grand Marnier or Kahlua
substitute other flavorings for vanilla, such as lemon or almond
dissolve instant coffee in the milk for a light coffee flavor