Egg white powder is a dehydrated form of egg whites, and once reconstituted, they can be used in any recipe without the need to cook them. Mix 2 teaspoons of powdered egg whites with 2 tablespoons of warm water for the equivalent of one large egg white, which can be used as a substitute in most recipes or added to smoothies, cheesecake bars, meringue frosting, cloud bread, or royal icing.