Place egg whites, sugar, salt, water, and corn syrup in top of double boiler.
Place over boiling water and beat constantly with a large double rotary beater or elecric mixer at high speed until frosting will stand in peaks, about 7 minutes.
Remove from heat; beat in vanilla.
Quickly spread on cake.
Makes enough frosting for top and sides of 2 9 inch layer cakes or 2 dozen cupcakes.
Seven-Minute Frosting Variations Chocolate Frosting: Stir into beaten frosting 2 ounces (2 squares) melted chocolate.
Coconut Fr osting: Sprinkle Plain, tinted, or toasted coconut over frosting while still soft.
Coffee Frosting: In master recipe, omit vanilla.
Substitute coffee for water.
Colored Frosting: Tint frosting as desired with food coloring.
Flavor as desired.
Fruit Frosting: Prepare master recipe.
Fold in 1/2 cup chopped candied cherries, chopped candied pineapple, or other candied fruit into beaten frosting.
Lemon Frosting: In master recipe, substitute 2 Tablespoons lemon juice and grated rind of 1 lemon for 2 tablespoons water, corn syrup and vanilla.
Orange Frosting: In master recipe substitute 3 tablespoons orange juice snd grated rind of 1 orange for 3 tablespoons water, corn syrup, and vanilla.
Marshmallow Frosting: Follow master recipeand fold in 1 dozen quarted marshmallows with flavoring.
Peppermint Candy Frosting: Prepare master recipe.
Fold 1/4 cup crushed hard peppermint candy into beaten frosting.
Gsrnish sides of cake with additional 1/4 cup crushed hard peppermint candy.
Seafoam Frosting: Omit corn syrup in master recipe.
Substitute 1-1/2 cups brown sugar for granulated sugar.