Boiled Icing
["2 c. sugar", "1/2 c. water", "1 Tbsp. vinegar", "2 egg whites", "1 tsp. vanilla"]
["Let sugar, water and vinegar cook to soft ball.", "Pour 1/2 of syrup slowly over stiffly beaten egg whites.", "Continue beating. Return remaining half of syrup to stove.", "Cook until hard ball stage.", "Pour slowly over other mixture, beating continuously until proper thickness to spread."]
["sugar", "water", "vinegar", "egg whites", "vanilla"]