Make a homemade egg substitute by combining 2 1/2 cups potato starch, 1 1/2 cups tapioca starch, 2/3 cup baking powder and 1/3 cup baking soda. Use a rounded 1/2 tablespoon of the powder and 2 tablespoons water to replace each egg in baking recipes.
Some ingredients, such as banana or potato starch, may be used as-is to replace eggs in a recipe. Depending on what purpose the egg serves in the recipe, certain replacement ingredients may be more effective than others. In some recipes, eggs add extra moisture. For these types of recipes, replace an egg with a liquid ingredient such as 1/4 cup pureed silken tofu, 1/4 cup yogurt or soy yogurt or 1/2 pureed banana.
Eggs also act as binders in some recipes. Binders help strengthen dough and prevent baked goods from crumbling after they bake. To make a binding replacement for 1 egg, combine 1 heaping tablespoon soy flour with 2 tablespoons water. In the place of soy flour for this recipe, use a tablespoon of corn starch if desired.
Eggs act as leavening agents in cake recipes, making the final product light and fluffy. Leavening egg replacements include 1/2 cup buttermilk or 1/3 cup applesauce for 1 egg or 1 12-ounce can of soda for 3 eggs.