Seven Minute Frosting

Combine sugar, corn syrup and water in a 1-quart saucepan. Cover and heat to a rolling boil over medium heat. Uncover and cook, without stirring, to 242°F (115°C) on a candy thermometer or until a small amount of mixture dropped into very cold water forms a ball that flattens when removed from water. Cooking time can take between 4 to 8 minutes. Meanwhile using an electric mixer at high speed, beat egg whites in a medium bowl just until stiff peaks form. Reduce speed to medium and while beating constantly, very slowly pour hot syrup in a steady, thin stream into the egg whites. Add the vanilla and continue beating at high speed for about 10 minutes until stiff peaks form.