Boiled Frosting

Combine sugar, water, and corn syrup small saucepan.Cook over medium heat, until sugar is dissolved and mixture begins to boil. Boil without stirring, until candy thermometer reads 242° F or mixture will spin a thread 6 to 8 inches long when dropped from tip up spoon. Just before serve reaches temperature, pour served 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.