Old-Fashioned Chocolate Icing
["2 c. sugar", "1 1/2 sticks margarine", "1 large can evaporated milk", "4 1/2 heaping tsp. cocoa", "1 tsp. vanilla"]
["Mix sugar and cocoa in thick or heavy pot.", "Add milk to moisten.", "Add remainder of milk gradually, stirring continuously. Add remaining ingredients.", "Place on burner, medium-high, stirring constantly.", "Cook for 20 minutes or until it won't boil up."]
["sugar", "margarine", "milk", "cocoa", "vanilla"]