1. Preheat your oven to 170℃ (350°F). Grease and line three 8-inch round cake pans with parchment paper.
2. In a large mixing bowl, sift together the all-purpose flour, cocoa powder, sugar, baking soda, baking powder, and. Whisk them until well combined.
3. In a separate bowl, beat the eggs lightly. Then add the buttermilk and vegetable oil, whisking until well combined.
4. Gradually add the wet mixture to the dry ingredients, mixing on medium speed until smooth. You can use a hand mixer or a stand mixer for this.
5. Carefully stir in the hot espresso coffee (hot water and espresso mixed). The batter will be thin. Mix until it is evenly combined.
6. Evenly distribute the batter among the three prepared cake pans
7. Place the pans in the preheated oven and bake for 40-45 minutes, or until a toothpick inserted into the center of the cakes comes out clean.
8. Let the cakes cool in their pans for about 10 minutes. Then remove them from the pans and let them cool completely on a wire rack.

Frosting

1. In a large mixing bowl, combine the softened butter and cream cheese.

   Use a hand mixer or stand mixer with a paddle attachment to beat them on medium speed until the mixture is smooth and creamy, about 2-3 minutes.
2. Pour in the cooled, melted dark chocolate and the vanilla extract.
3. Continue to mix on medium speed until these ingredients are fully incorporated and the mixture is smooth.
4. Gradually add the sifted icing sugar and cocoa powder to the bowl. Beat until the frosting is smooth and creamy.