Snowy Boiled Icing

Combine sugar water salt and vinegar in a saucepan. Cook and stir over medium heat just until clear. Then cook without stirring until syrup spins a long thread when dropped from tip of spoon or to 240 degrees F (115 degrees C).

Beat egg whites until soft peaks form. Add syrup in a very thin stream beating constantly. After all syrup is added continue beating until frosting will hold its shape. Mix in vanilla.