In a mixing bowl, combine the butter, brown sugar, and sugar. Beat with an electric mixer for 1 minutes, until smooth and fluffy. Add in the peanut butter, egg, and vanilla extract, beat again, less than 1 minute. Add in the flour, baking soda, baking powder and salt, mixing with a spatula just until there are small flour streaks left - it’s okay if the batter has clumps! Be careful not to over mix. Gently mix in the reese's pieces and chocolate chips until combined.
Use a small cookie scoop to form balls from the dough. Add additional reese's pieces or chocolate chips to the dough balls if desired. Place the cookies on a silicone lined baking sheet and bake for 12 minutes or until the edges of the cookies begin to turn golden and the tops begin to crack slightly. Bake the cookies in batches so you don’t crowd the baking sheet.
Allow the cookies to cool completely before serving.