Remove the cake from the freezer and cut around the edges to release from the springform pan. Pour the remaining ganache over the cake and use a cake spatular to spread the ganache evenly over the top and sides of the cake. Refrigerate the cake for 10 to 15 minutes to set the ganache. Fill a pastry bag fitted with a large star tip with the chocolate mousse. Pipe a circle of stars (each touching the other) along the outside edge of the top of the cake. Continue to pipe out circlaes of stars until the top of the cake is covered. Refrigerate the Death by Chocolate for at least 4 hours, and prefreably 12 hours, before cutting and serving. Prepare the Mocha Rum Sauce ( the sauce may be prepared just prior to serving or several hours in advance). To serve, cut the Death by Chocolate into the desired number of servings. Heat the blade of a serrated slicer under hot running water before slicing into the cake. Repeat this procedure after cutting each slice. Before placing the cake slice on the 10" diameter plates, flood the base of each plate with 3 or 4 T Mocha Rum Sauce, then place a piece of Death By Chocolate in the center of each plate. Serve immediately.