Lightly butter and flour four 6" cake pans (I use cake strips as well)
Sift the flour, cocoa powder, baking powder, baking soda, and salt into a medium bowl.
In a small bowl, combine the coffee and buttermilk.
In the bowl of your electric mixer, or with a hand mixer, beat the butter until smooth and creamy.
Add the sugar and continue beating until the mixture is fluffy (this will take about three to five minutes).
Scrape down the sides of the bowl as needed.
Add the eggs, one at a time, mixing well after each addition.
Add the vanilla extract and beat to combine. Then add the melted chocolate and beat until incorporated.
Add the coffee/buttermilk mixture and flour mixtures in three additions, beginning and ending with the flour mixture. Beat only until the ingredients are mixed together.
Divide the batter evenly among the three prepared pans and smooth the tops.
Bake for about 30 – 35 minutes or until a toothpick inserted in the center comes out clean and the tops spring back when lightly pressed.
Rotate the pans about halfway through baking to ensure even baking.
Remove from oven and place on a wire rack to cool for about 15 minutes. Butter or lightly spray with a non stick vegetable spray a wire rack before inverting the cakes onto the rack to prevent the cakes from sticking. Cool the cakes completely before frosting.
For the Chocolate Buttercream:
Cream butter and sifted cocoa powder.
Mix in powdered sugar, vanilla and milk.
For the Chocolate Ganache:
Melt chocolate and cream.
Transfer to piping bag or spoon in-between each layer.
For the Black Buttercream:
Cream butter.
Mix in powdered sugar, vanilla and milk.
Add in black food coloring until desired. (The buttercream will darken after it's piped by the way.)
Notes
Tip size: "large round tip." You wanted you could literally cut the tip of a pastry bag.