Trim the edges of the cake. Cut the rectangle into 3 even pieces each should be about 10 inches x 5 inches
Melt the 70 g of chocolate in the microwave or a double broiler. If using the microwave be sure to check and stir in 30 second increments
Place one piece onto a board or serving tray. Pour the melted chocolate on top and spread in an even layer so there is a thin layer of chocolate coating the entire cake. Allow the chocolate to harden
After the chocolate has hardened, flip over the layer so the chocolate becomes the bottom of the cake. Dab 1 tablespoon of kahlua evenly across the side of the sponge without the chocolate
Top with ~½ cup coffee buttercream and spread it into an even layer with an offset spatula
Top with another layer of the cake and dab 1 tablespoon of kahlua evenly across the sponge
Top with ~½ cup of chocolate ganache and spread it into an even layer with an offset spatula
Top with another layer of the cake and dab 1 tablespoon of kahlua evenly across the sponge.
Top with ~½ cup coffee buttercream and spread it into an even layer with an offset spatula. At this point set the cake in the fridge until it is hardened
After it has hardened, Top with ~½ cup of chocolate ganache and spread it into an even layer with an offset spatula
Optional use any remaining ganache to pipe on detail