So, some cookie recipes call for both baking soda and baking powder, and some call for one or the other. This small batch chocolate chip cookie recipe calls for both. Baking soda is acidic, which reacts with the ingredients the dough to create air bubbles, which spreads the dough, sometimes causes cracks (in the case of our sugar cookies) and makes it lift, ever so slightly. Baking powder, on the other hand, creates a high rise and plenty of lift in a cookie. This is why we use it in our Strawberry Shortcake Cookies--we want tall, fluffy cookies in the case of shortcake cookies. For chocolate chip cookies, we want both spread and lift, so we use both.