Combine sugar, water and corn syrup in small saucepan. Cook over medium heat, stirring constantly until sugar is dissolved and mixture begins to boil.

Boil without stirring until 242° or mixture will spin a thread.

Just before syrup reaches temp, beat egg whites until stiff but not dry.

Pour syrup in thin stream over egg whites while beating at high speed.

Continue beating until mixture stands in stiff, glossy peaks.

Beat in vanilla.

Cool slightly, spread on sides and top of cake.