Start with making chocolate chip cookie dough. Cream butter and sugars together until light and fluffy. Stir in vanilla and egg. Dump in baking powder, baking soda, salt and flour. Stir together. Fold in chocolate chips. Wrap in plastic and place in fridge.
Combine brownie mix, egg, butter, water and flour in a large bowl. Fold in chocolate chips. Wrap in plastic wrap and place in fridge until oven is fully preheated. Preheat oven to 350 degrees F.
Take 1 tablespoon of each cookie dough and push them together, roll them into a ball, and place them onto a cookie sheet lined with parchment paper or a silicone liner. Bake for 9-11 minutes until cookies are set and start to turn golden.
Allow to cool for 4-5 minutes on the cookie sheet before removing to a cooling rack to cool completely. Repeat with remaining cookie dough on a cooled cookie sheet.
Adapted from Like Mother Like Daughter