Aquafaba
Egg whites may easily be replaced with aquafaba. The liquid left over after boiling beans or legumes is known as aquafaba. The liquid is the same as that in canned beans or chickpeas. The liquid is a great substitute for many recipes because it has a consistency that is very similar to that of raw egg whites.
To substitute 1 egg, use 3 tablespoons (45 grams) of aquafaba. Try it by pouring the chickpea water through a filter into a mixer and whipping it into a fluff that can be used to make everything from mayo to macarons to a gluten-free raspberry lemon pavlova. Recipes that just call for egg whites, such as meringues, marshmallows, macaroons, or nougat, work well with aquafaba.