The Chocolate Chip Cookie is iconic. Really, any cookie with chocolate chips can be called a chocolate chip cookie, but it would never live up to it's name since it is ultimately associated with a buttery brown sugar dough.
Some like them crispy, some like them chewy. I like them both ways - crispy on the outside, chewy in the middle. To me, a perfect Chocolate Chip Cookie is rich and buttery with a pronounced caramelized flavour enhanced by pure quality vanilla extract. It is as much about the dough as it is the chocolate, and it should always be slightly undercooked to sustain a moist & chewy interior. This also translates to denseness in that the ultimate Chocolate Chip Cookie shall never be cakey...never ever....ever. So here is the best advice I can give you today:
Do not trust a Chocolate Chip Cookie recipe that uses baking powder. As a matter of fact, never trust a Chocolate Chip Cookie recipe that uses more than 1/2 teaspoon of baking soda for a yield of 2 dozen cookies.
What happens if there is too much baking soda?
Too much baking soda can result in a bad Chocolate Chip Cookie for several reasons. Firstly, it can carry the carbon dioxide-producing reaction too far, depending on the recipe, and create too many gas bubbles that produce a cake-like cookie. Secondly, if more baking soda is added than what is actually required to carry the reaction to completion (i.e. to use up all of the acidic components in the dough), then residual sodium bicarbonate left in the cookie will leave a bad aftertaste.
So, if you ever meet a Chocolate Chip Cookie with baking powder, you have the right to believe that it is an impostor. A little leavening goes a long way in this classic treat and careful evaluation of the recipe should be performed before succumbing to an impromptu baking frenzy.