Preheat oven to 350°
Line a cookie sheet with parchment paper.
In a small pot, melt the butter and chocolate gently until smooth. Let cool a few mins.
In a mixer, beat eggs, sugar and vanilla.
Stream in the chocolate mixture and blend.
Add flour, baking powder and salt.
Use a small ice cream scoop and scoop 6 onto the cookie sheet.
Bake approx 8 mins.
Cool 1 min on sheet and then flip half over placing the reese's cup on top. Top with the other cookie to create a sandwich and let cool on a wire rack.