Egg whites are the best substitute for meringue powder. Spiceography shares that, before meringue powder existed, egg whites were the go-to ingredient and suggests that your final baked goods and desserts actually taste better when you use egg whites over meringue powder. However, the publication also notes that, if you need to whip up a lot, that can be a challenge. If you are going to use egg whites, you will need to add some cream of tartar along with a little lemon juice to help prevent all of those beautiful egg whites you have spent the last 20 minutes whipping up from sinking. Blogger Jessica Gavin explains that it is the egg whites’ “foaming capability” that makes them a superior alternative compared to others.
But, according to Reddit users, it might take some time to master using egg whites in place of meringue powder. Redditors shared they found pasteurized egg whites to be “temperamental.” That said, one pro suggested that you could try unpasteurized egg whites, writing, “You don’t need pasteurized egg whites, but someone mentioned they found the egg white temperamental. Unpasteurized will be more temperamental, which is the primary reason for the suggestion, but still 100% useable. I used unpasteurized this Christmas. Also pro tip: avoid bubbles in your egg whites, also makes it needlessly temperamental.”