Adjust the oven rack to the center of the oven and preheat the oven to 350 degrees.
Butter two 9″ x 2″ cake pans and line the bottoms with circles of parchment paper.
Sift together the cocoa powder, cake flour, salt, baking soda, and baking powder in a bowl.
In the bowl of a standing electric mixer, or by hand, beat together the butter and sugar about 5 minutes until smooth and creamy.
Add the eggs one at a time until fully incorporated. (If using a standing electric mixer, stop the mixer as necessary to scrape down the sides to be sure everything is getting mixed in.)
Mix together the coffee and milk.
Stir half of the dry ingredients into the butter mixture, then add the coffee and milk. Finally stir in the other half of the dry ingredients.
Divide the batter into the two prepared cake pans and bake for 25 minutes, or until a toothpick inserted into the center comes out clean.
Melt the chopped chocolate with the cream in a heatproof bowl set over a pan of barely simmering water, stirring occasionally until melted.
Remove the bowl from the pan of water.
Cut the butter into small pieces and whisk them into the chocolate until completely melted and the Ganache is smooth.
Cool until spreadable, which may take about 1-2 hours at room temperature
When the cakes are done, take it out of the oven and cool completely before turning them out of their tins.
Tilt one cake out of the pan, remove the parchment paper from the bottom and invert it back onto a cake plate.
Spread a good-sized layer of icing over the top.
Top with the second cake layer and spread the top and sides with the remaining icing as decoratively as you want.