How to make
Preheat the oven to 360°F (180 °C). Melt the butter with the coffee and add the buttermilk. Put the eggs and sugar in the mixer bowl and beat them at low speed. In succession, add the flour, salt, cocoa, baking powder and baking soda. Beat them until mixed.
Add the vanilla and coffee mixture, then stir well again. You can use several cups or a cake form. Spray the forms with vegetable oil or cooking spray and pour the mixture into it. Bake for 15-20 minutes. To prepare the ganache, heat the cream in a pot with a thick bottom, until bubbles begin to form around the edge.
Pour the chocolate in a large bowl. Add half the cream and leave it to sit for 30 seconds for the chocolate to melt. Mix to get a homogeneous mixture. Then add the remaining cream and mix again. Remove the cake from the cake form or cups and leave it to cool on a cooking grid placed over a tray, covered with baking paper.
Once cooled, brush the cake with plenty of ganache and allow the excess to drain away. Move the chocolate cake to a platter. Optionally, you can make chocolate shavings from white chocolate.
Using a vegetable peeler, cut thin slices of white chocolate and decorate with them. Another option is to sprinkle the cake with crushed nuts of your choice.