Place grated chocolate in bowl. Pour 1/3 of whipping cream in a small pan and cook on low heat almost to a boil. Remove from heat. Add chocolate and cinnamon and blend gently and well. Set aside.
In an electric mixer, add the remaining whipping cream until firm consistency. Incorporate the chocolate mixture using a wooden spoon. Add cocoa blend gently and well. Refrigerate the mousse for several hours.
