Cut the swiss roll cake into three pieces (about 3cm thickness) and set aside.
Cut/break Pepero sticks to separate the chocolate coated part and not coated part (yellow handles) and set aside. (We will only use the chocolate coated part for the recipe.)
Shell the pistachio nuts, coarsely chop them and set aside.
Add the chocolate into a bowl and melt it by microwaving it. (I heated for 1 mins and 30 seconds. However, this will vary depending on the power of your microwave.) Once the chocolate is melted, add the heavy cream into the chocolate bowl and mix them well.
Stack the swiss roll cake and pour the chocolate mixture on the outer layer of the cake. Spread it with a bread knife.
Stick the Pepero around the cake wall and decorate the top of the cake with the pistachio nuts. Serve.