Grease the cake pans and line them with parchment paper cut to measure to cover the inside bottom of the pans. Grease the paper with butter
In a medium bowl, sift the flour and the cocoa powder. Add the sugar, baking powder, baking soda, salt and espresso powder. Whisk them together and set aside.
In a larger mixing bowl whisk together the egg, oil, buttermilk, coffee and vanilla extract.
Working in batches, add the dry ingredients on to the wet ingredients, mixing well before each addition
Divide the batter evenly between the two pans. Bake for about 30 minutes, checking at the 25 minute mark for doneness. Ideally, the center should still look slightly shiny when you take it out of the oven, as it will continue cooking after you remove it from it
Let the cakes cool down completely.
Make the frosting:
Sift the instant espresso granules through a very fine sieve to make the powder as fine as possible.
In a mixing bowl or stand up mixer, beat the butter on high until creamy. Add the cream cheese and beat together. Lower the speed and add the icing sugar, one half cup at a time, making sure it’s all well blended before adding the next half cup. Finally, add the vanilla extract and mix together.
Fill a large cake decorating bag fitted with the star tip with the espresso icing. Close it with an elastic band, place it in a jug (or a cup tall enough to hold the bag standing up) and place in the refrigerator for about 30 minutes.
Assemble the cake:
If the cakes have a slight dome, cut the top horizontally with a large bread knife. Discard the tops (or eat them, like I did!)
Place one cake on a surface, cut side up. Spread a thick layer of frosting onto the cake.
Place the second cake on top, cut side down so the flattest surface (the bottom of the cake) faces up. Press down the cake slightly. The frosting will push to the sides. If necessary, pipe some more frosting to fill all the grooves. Slide an icing smoother along the sides of the cake
Next, spread a thin layer of icing over the top of the cake, smoothing and blending the edges.
Decorate the top by piping a generous amount of frosting forming small curls. Finally, sprinkle with chocolate bits.
Notes
You can take the cake out of the refrigerator 30 minutes before it will be served so the espresso cream cheese frosting softens a bit
The cake will last for a few days in the refrigerator (if there's any left, that is!). Make sure you cover the cut sides with plastic wrap to keep them moist