Preheat your oven to 350°F (180°C) and prepare two 8-inch round baking pans by lining the bottoms with parchment paper and lightly greasing the sides.

In a large mixing bowl, combine the flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt. Whisk together until well-blended.

Add the eggs, buttermilk, vegetable oil, and vanilla extract to the dry ingredients. Mix gently until the batter is almost combined; a few lumps are okay.

Pour in the hot coffee, stirring gently to combine until the batter is smooth and free of lumps.

Divide the batter evenly between the prepared baking pans. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.

Once baked, remove the cakes from the oven and let them cool in the pans for 10 minutes. Transfer the layers onto wire racks to cool completely.

In a medium saucepan over low heat, melt the unsalted butter along with the heavy cream and dark chocolate, stirring until smooth. Sift in cocoa powder and powdered sugar, mixing until glossy.

Once the frosting is smooth, cover the surface with plastic wrap and allow to cool in the refrigerator for 1-2 hours.

Once the cakes are cool and the frosting is ready, place one cake layer on a serving plate and spread about ⅓ of the frosting on top. Place the second layer on and frost with remaining frosting.

Create texture on the frosting with an offset spatula for an elegant finish. Optionally decorate with chocolate shavings or sprinkles.