3/4 c. sugar
1/4 c. water
2-3 egg whites
1 tsp. vanilla

Put sugar and water in pan. Boil it until it spins a thread off the spoon. In the meantime beat the egg whites until stiff. Then pour sugar syrup into egg whites while continuing to beat. Add vanilla. Beat until well blended. Spread on cake. (I often double this recipe with good results).