Begin preparing the pudding cake the day before serving. Make the chocolate pound cake and the chocolate pudding as directed the day before; cool the cake and chill the pudding overnight.
To make this cake a chocolate orange pudding cake, make the chocolate pudding as directed, but use 10.5- oz Lindt Intense Orange chocolate or Green & Black’s Maya Gold chocolate (3 bars) in place of the chocolate called for in the pudding.
In the morning of service, assemble the cake: cut pound cake horizontally into 4 equal layers. Line inside of clean 10-inch springform pan with aluminum foil. Place top layer of cake in bottom of pan. Cut up the 4th layer to fill the hole left from the 10- inch tube pan. Spoon 1/3 of pudding over cake layer in pan. Top with the next cake layer, fill the hole with extra cake, and top with half of remaining pudding. Place bottom cake layer, bottom side up, in pan, fill the hole with extra cake, and top with remaining pudding. Cover loosely with plastic wrap and refrigerate until well chilled.
Before serving, warm chocolate ganache until melted. Stir 2 T grand marnier or other orange- flavored liqueur into the melted ganache. Serve chilled cake wedges with warm chocolate sauce and candied orange rind, if desired. Makes 16 servings.