Some royal-icing recipes call for meringue powder, which consists mostly of powdered egg whites and additives to increase shelf stability. If you don’t have meringue powder on hand, no need to go on a hunt for this elusive ingredient—two easy substitutions yield the same taste and texture.
Powdered egg whites offer the most seamless substitution because the ingredient is essentially the same thing as meringue powder. There’s no need to convert anything and no additional steps—replace at a 1:1 ratio. Powdered egg whites are generally available in most grocery stores and hobby stores (in the confection aisle).
Egg whites are obviously the easiest and least expensive option and have been used for hundreds of years to make meringue. One egg white equals 1 tablespoon meringue powder. The sugar and other additives are minuscule and do not need to be accounted for in the substitution.
If you’re concerned about you or your guests consuming raw egg, you can heat the egg whites with sugar to kill any bacteria or salmonella. However, you need to reduce the sugar in the rest of the recipe.
How to Make a Safer Meringue With Egg Whites
Bring 1 inch of water to a boil in a skillet. In a stainless-steel bowl, add 2 tablespoons water, 1/8 teaspoon cream of tartar, 2 egg whites, and 4 tablespoons sugar, and whisk. Place the bowl in the skillet and stir the mixture with a rubber spatula for 1 minute. Remove the bowl and check the temperature with a candy thermometer; it should read over 160 degrees Fahrenheit. Use this mixture to make meringue, and subtract 4 tablespoons sugar from the rest of the recipe.