Mix together mascarpone, egg yolks, sugar, cinnamon and a little rum. Beat egg whites until stiff and fold in carefully. Line the dessert bowls with the ladyfingers and drizzle with rum. Sprinkle very lightly with coffee powder. Pour the cream mixture over the ladyfingers. Sprinkle thinly with cocoa powder. Decorate with the grated chocolate and chill for a long time to steep.