Cook sugar, corn syrup, and water in a saucepan over low heat, stirring constantly until sugar dissolves. Cover then cook for 2 to 3 minutes longer. Uncover and continue cooking to the firm ball stage 244 to 248 degrees F (118 to 120 degrees C). Remove from heat.
Beat egg whites in a large mixing bowl with the vanilla extract, almond extract, and salt until stiff but not dry.
Pour hot syrup in a slow, steady stream over beaten egg whites, beating constantly. Continue beating until frosting stands in peaks and begins to lose its gloss, about 10 minutes. If necessary, thin with a few drops of cream.