Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper.
In a large bowl, cream together softened butter, peanut butter, granulated sugar, and brown sugar until smooth and fluffy.
Add eggs one at a time, beating well after each addition.
In a separate bowl, whisk together flour, baking soda, and salt; gradually add to the wet mixture and mix until combined.
Fold in chopped mini peanut butter cups.
Scoop dough by rounded tablespoons onto prepared baking sheets, spacing cookies about 2 inches apart.
Bake for 12 minutes or until edges are lightly browned. Remove from oven and cool on baking sheets for 5 minutes before transferring to wire racks to cool completely.
Notes
Store cookies in an airtight container at room temperature for up to 5 days or freeze for longer storage.