Mix the room temperature butter with the sugar and then add in the cocoa powder. melt your dark chocolate and then mix in once it's cooled. crumble and add in a handful of cookies until you reach the consistency you prefer (about 20 cookies). place the mix on a sheet of parchment paper and roll it up tightly into a shape of a salame. tight both ends and put in the fridge for about 4 hours. dust with powdered sugar.