THE LAYERS in this delicious chocolate cake are moistened with orange juice and Grand Marnier in place of the traditional sugar syrup. You can serve it just as is, or decorate it with Royal Icing or candied orange peel.
Using a serrated knife, cut the chocolate génoise into two layers. Turn the top layer cut side up on the rack. Using a pastry brush, moisten both layers with the flavored orange juice. (Several tablespoons of juice will remain when making an 8-inch cake.)
Place the cake, on the wire rack, over a baking sheet. Spread an even layer of ganache over the bottom layer.
Replace the top layer. Pour the remaining ganache over the top of the cake so it runs down the sides. Tap the rack on the pastry sheet to help the ganache fall evenly. If there are spots that were missed, coat them with the excess ganache from the pastry sheet, using your spatula.
Refrigerate or freeze the cake on the rack. When the icing is firm, transfer the cake to a doilied serving plate. (The cake will keep refrigerated for several days, or can be frozen for several weeks. Bring to room temperature before serving.)