Step 1: Cream together the softened butter, creamy peanut butter, granulated sugar, and light brown sugar until the mixture is light and fluffy.
Step 2: Add the eggs one at a time, beating well after each addition, then stir in the vanilla extract.
Step 3: In a separate medium bowl, whisk together the flour, baking soda, baking powder, and salt.
Step 4: Gradually add the dry flour mixture to the wet butter mixture, mixing on low speed until just combined.
Step 5: Fold in the Reese's peanut butter chips and chopped mini peanut butter cups using a spatula.
Step 6: Cover the dough and refrigerate for at least 30 minutes to ensure the cookies don't spread too much.
Step 7: Preheat your oven to 350°F (175°C) and line two large baking sheets with parchment paper.
Step 8: Scoop 2-tablespoon-sized portions of dough and place them on the baking sheets, spaced 2 inches apart.
Step 9: Bake for 10-12 minutes, or until the edges are golden but the centers still look slightly soft.
Step 10: Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.