Reeses's Peanut Butter Cup Cake

My brother-in-law is a a huge fan of Reese's cups. For his birthday I made this chocolate cake with chocolate peanut butter butter cream icing. 9"x3" pan then I split it into 2 layers to fill with icing. I smoothly iced the top and then piped using a #21 tip vertically around the sides of the cake, piped swirls of icing to stick the mini cups on the cake and then surrounded the cake with mini cups.