1. Preheat oven to 350 degrees F. Line a baking sheet with parchment paper.

2. In the bowl of a stand mixer, beat together butter, brown sugar, and peanut butter until light and creamy, about 2-3 minutes. Add in egg and vanilla extract and beat. In a small bowl, whisk together flour, baking powder, baking soda, and salt until combined. With the mixer running, incorporate the dry mixture just until combined. The dough should be tacky, but not sticky.

3. Roll dough into 2 tablespoons sized balls and place 6 on the prepared baking sheet, leaving plenty of room in between for spreading. Gently press a mini Reese’s peanut butter cup into the center of each ball on the baking sheet. Top each cookie with another ball of dough and use your hands to press the two balls of dough together around the peanut butter cup. Repeat with remaining cookie dough.

4. Bake for 14-16 minutes and let cool on the pan for 10 minutes before transferring to a cooling rack. Allow cookies to cool completely.

5. If drizzling with chocolate, melt the chocolate melting candy according to package instructions and pour into a piping bag or sandwich bag with a tiny tip cut from the corner. Drizzle chocolate over cookies and allow chocolate to set before serving.