Mix the popcorn and the melted chocolate. Pour the mixture into a silicone cake mould. Refrigerate for at least 2 hours or use a freezer to make the chocolate set faster. Mix all the ingredients for the caramel sauce in a sauce pan and cook at middle heat for 7 minutes constantly stirring. Pour the caramel into a bowl to cool. Remove the cake from the silicone mould and decorate with caramel sauce.