What Role Do Eggs Play Exactly When It Comes To Baking Cookies?

If you've ever made cookies at home, then you know that just about every recipe calls for eggs. But what you may not know is the exact function that eggs play in the baking process— why do all those cookie recipes require eggs?

Essentially, eggs contain key components that are needed for the right outcome of a cookie: the egg white contains protein and water, which will soften the cookie, while the egg yolk has fat, which will balance the flavor. Egg yolks also help to keep all of the ingredients together, so, with cookies, they're needed to achieve the right consistency of the dough. And egg whites can help get the cookies to a fluffy end result. Using whole eggs will result in a cookie that has a cake-like texture with a rich flavor. So what happens to cookies if you keep the eggs out?

Let's say, like mentioned above, you have all the ingredients for cookies except for eggs and you decide to just see what happens going through with the recipe just the same — except without the eggs. What would happen? Cookies will fall apart extremely easily because they lack the yolk to hold them together. Additionally, they'll be really dense because the egg whites weren't there to lighten and make them fluffy.

Meanwhile, sticking to just egg whites will result in a dough that contains too much moisture and cookies that are too dense, too thin, and too moist. On the other end of the spectrum, if you use just egg yolks, the cookies will also be too thin, as well as too dry. So, all in all, it's definitely best to stick to whole eggs when it comes to cookie recipes. And if you don't have eggs, then you need to find the right replacement so that the function of the egg is still covered. Some common egg replacements include mashed banana, applesauce, yogurt, and silken tofu (specifically silken, firmer tofus won't work) — for each of these, use ¼ replacement per egg.