Meringue powder is a pasteurized egg product which is designed to replace beaten egg whites in recipes. The primary advantage of meringue powder is that since it is pasteurized, it does not contain potential sources of food borne illness such as salmonella. This trait makes it ideal for recipes which call for uncooked egg whites. Many baking supply stores sell meringue powder, and it can sometimes also be found at more general markets.

This product is made by drying egg whites and mixing them with cornstarch and gum, creating a white powder. When moistened, the cornstarch and gum help the meringue powder bind together, creating a passable substitute for fresh raw egg whites. Flavorings like vanilla are often added as well, partially to cut down on the slightly starchy taste of meringue powder.

As long as meringue powder is kept in a cool dry place, it has a fairly long shelf life. To use it, cooks simply measure out the desired amount and rehydrate it. Many recipes which call for beaten egg whites have specific measurements for meringue powder, although these recipes may require some tweaking to come out just right, as different brands rehydrate differently.

One of the most common uses for meringue powder is in royal icing, a glaze which is sometimes used for cookies. It can also potentially be used in egg nog and in other recipes which call for beaten egg whites, although your mileage may vary. It is also important to stress the fact that meringue powder is not a replacement for eggs in recipes, merely for beaten egg whites, and it may be helpful to know that despite the name, meringue powder does not actually make very good meringue.

You may want to experiment with meringue powder a bit before committing to it, because it can behave strangely in some recipes. If you know that you are going to be making something like cookies for people with compromised immune systems, plan on mixing up a couple of batches of icing before you find one which works perfectly, and be prepared to adjust the levels of spicing in your recipe to help cover up the flavor of the meringue powder, which can sometimes be quite strong.