Lesson learned

A few weeks ago I came across a delicious (flour free) peanut butter cookie recipe, and we spent the week enjoying fresh cookies.
Yesterday I remade the same recipe, except that this time the cookies turned out more like lumpy blobs of peanut butter in a vague cookie shape and texture. One bite of one calls for a glass of water. They're not inedible, they're just....not good.

Ingredients for the cookies:
1 c. peanut butter
3/4 c. sugar
1 T baking soda
1/2 tsp vanilla
1 egg

Any guesses as to which ingredient I left out?


I'll give you a hint: it's not peanut butter, sugar, baking soda or vanilla.
DOH. Apparently eggs are, in fact, an important ingredient in cooking.