In a medium mixing bowl, whisk together the flour, baking powder, baking soda, and salt; set aside.
In a large mixing bowl (or the bowl of a stand mixer), cream the butter, brown sugar, and granulated sugar together with an electric mixer on medium speed until light and fluffy (about 5 minutes). Add the egg and vanilla and beat until combined.
Add the flour mixture and beat at medium speed just until combined. Stir in the chocolate chips.Note: the dough will be very firm and a bit crumbly but should form a ball when pressed together.
Split the dough into six equal portions and shape each into a ball. Tip: use a round ½ cup measuring cup to make it easier to shape each cookie dough ball.
Place the dough balls on a large cookie sheet lined with parchment paper. Cover the cookie sheet with plastic wrap and refrigerate for 2 hours.
Preheat the oven to 400F.
Remove the plastic wrap from the cookie sheet. Bake the cookies at 400F for 15-18 minutes until set and golden brown around the edges.
Allow the cookies to cool on the cookie sheet for 5 minutes, then remove to a cooling rack to cool completely.The cookies can be served warm or at room temperature.