Preheat your oven to 350°F (175°C) and line a large baking sheet with parchment paper.

In a stand mixer, cream together the salted butter, brown sugar, and peanut butter until light and fluffy.

Add the large egg and vanilla extract and mix until combined, scraping down the sides as needed.

In a separate bowl, whisk together the flour, baking powder, baking soda, and salt. Gradually add to the wet ingredients and mix until just combined.

Roll the dough into 2-tablespoon-sized balls and space them on the baking sheet.

Press a mini peanut butter cup into the center of each dough ball, cover it with another dough ball, and seal the edges.

Bake for 14-16 minutes or until lightly golden around the edges. Cool on the baking sheet for 10 minutes.

Optionally, melt the chocolate melting candy and drizzle over the cooled cookies.