How to Make It
Whisk together the flour, baking powder, salt, and baking soda in a medium mixing bowl until combined; set aside.
Using a stand mixer or electric hand mixer, cream the butter, brown sugar, and granulated sugar for 5 minutes, or until light and fluffy. Scrape down the sides and bottom of the bowl with a rubber spatula. Add the peanut butter, vanilla extract, and egg; beat at medium-low speed until incorporated.
Add the flour mixture, beating at medium-low speed until just incorporated. With a rubber spatula, mix in the Oreos, peanut butter cups, and white chocolate chips by hand, scraping the sides of the bowl to incorporate any remaining flour. Cover the bowl and chill the dough 25-30 minutes.
Preheat oven to 375°F.
Form the dough into (1.75-ounce) balls, and flatten slightly with your hand. Place 2 inches apart on parchment paper-lined baking sheets. Bake 12-14 minutes, rotating pans halfway through baking. Cool on the pan 5 minutes, then transfer cookies to a wire baking rack to cool completely. Repeat with remaining dough until all cookies are baked.
If you prefer, you can swap the peanut butter in this recipe for cashew butter or a different nut butter of your choosing. You can also substitute any chocolatey candy you like for the Reese’s cups.