I need one egg for a cookie recipe but I am out of eggs. What can I substitute it with?

Answer 1

That's kind of tough, because the egg serves as a binding agent. There's not a lot of substitutes that won't affect the texture or outcome.

Unlike other ingredients, the egg isn't for flavor, it's for effect.

Answer 2

Arrowroot flour.
Potato flour
Ground flaxseeds (the best plant-based binder)

Add extra water if using dry substitutes.

Answer 3

There's a few suggestions here:

http://vegetarian.about.com/od/vegetarianvegan101/f/eggsubstitute.htm