1 box confectioners' sugar
1/2 c. cocoa
1 tsp. vanilla
1 stick butter
1/4 c. milk

Mix sugar, cocoa, vanilla, and milk together until blended. Put butter in center of mixture. Cook on high 2 minutes or until bottom of bowl is warm to touch. Remove from microwave and stir until mixed well and pour into dish and place in refrigerator for 1 hour. (If butter is not completely melted, it will melt as you stir).