What makes cookies fluffy?

Dana :)

I *think* it's the baking soda (or baking powder) that makes things fluffy. I believe it creates little gas bubbles and that makes it fluffy. I could also be wrong (I should probably Google it). But if you want less fluffy cookies you can decrease baking soda, and more fluffiness, increase it. Many flourless peanut butter cookies require egg, peanut butter, sugar, and baking soda, which helps it rise!