Preheat your oven to 350°F (175°C).

Line your baking sheet with parchment paper.

In a mixing bowl, combine the softened butter and peanut butter. Beat until smooth and creamy.

Mix in granulated sugar and brown sugar until well incorporated. Then add eggs and vanilla extract, mixing until light and fluffy.

In a separate bowl, whisk together flour, baking soda, and salt.

Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Gently fold in the chopped mini Reese's Peanut Butter Cups.

Using a cookie scoop, drop dough balls onto the prepared baking sheet, spacing them about 2 inches apart.

Bake for 10-12 minutes or until the edges are lightly golden and the centers are still soft.

Let the cookies cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.