Preheat the oven to 350°F (180°C) and prepare three 8-inch round baking pans.

In a large mixing bowl, combine the eggs, vegetable oil, and vanilla extract, whisk until smooth.

Gradually add the granulated sugar, cocoa powder, and buttermilk, mixing until glossy.

Stir in the kosher salt and hot coffee until smooth.

Gradually fold in the flour, baking powder, and baking soda until just combined.

Distribute the batter among the prepared pans and bake for 25-30 minutes.

Let the cakes cool in the pans for 10 minutes, then transfer to wire racks.

Beat the butter in a bowl until light and fluffy for frosting.

Gradually mix in powdered sugar and cocoa powder, then blend in melted dark chocolate.

Prepare ganache by heating heavy cream and pouring it over dark chocolate until smooth.

Whip the heavy cream, cocoa powder, and sugar until stiff peaks form for whipped cream.

Assemble the cake by layering and frosting each layer.

Apply a crumb coat and chill for 15 minutes, then frost with remaining buttercream.

Pour ganache over the cake allowing it to drip down the sides.

Decorate with whipped cream and cocoa powder or chocolate shavings before serving.