What do eggs do in cookies?

Question

Some recipes call for two eggs and some call for one. What's the difference? What happens if you put 1 egg in versus 2? What do the eggs do?

Answer 1

makes them tender and holds the cookie together.

An egg is a liquid but when cooked it solidifies.  So when an egg is baked into a cookie it solidifies in that cookie and holds it together.  

without eggs your cookie will crumble.  

and THAT is the way the cookie crumbles.  :0)

Answer 2

it makes cookies more tender, and it can make cookies more chewy and moist, it also adds flavor aside from binding. The amount of eggs in a recipe differ depending on the type of cookie, the texture and the amount of the other ingredients.  

Answer 3

the egg is a blinding agent

Answer 4

Eggs act as a binder and thickener in dough, which cookies are made from

Answer 5

Eggs are a binding agent.

It depends on the quantities of the batch you are preparing and how much you want them to spread while baking.

Answer 6

Eggs work as a binder and often give a bit of leavening action.

Answer 7

The eggs keep cookies from falling apart and crumbling (same reason you put an egg in meatloaf).  They also make them rise a bit (similar to an omlette).  They're also used as an emulsifier in things like Caesar salad dressing (to keep the oil and non-oil ingredients from separating).