Press strawberries through a fine wire sieve Combine egg whites, sugar, 5 tablespoons strawberry puree, corn syrup, and lemon juice in top of double boiler, beating with rotary egg beater until thoroughly mixed. Place over rapidly boiling water, beating constantly with rotary egg beater, and cook 6 to 7 minutes, or until frosting will stand in peaks. Remove from boiling water and beat until thick enough to spread. Makes enough frosting to cover tops and sides of two 8-inch layers.