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

In a large mixing bowl, whisk together the flour, granulated sugar, cocoa powder, baking powder, and baking soda.

Add the room-temperature eggs, vegetable oil, vanilla extract, and buttermilk to the dry mixture and stir until smooth.

Blend in the kosher salt and hot coffee into the batter until fully mixed.

Divide the cake batter evenly between the prepared baking pans and bake for 25-30 minutes.

Cool the cake layers in the pans for about 10 minutes, then transfer to a wire rack to cool completely.

Beat the room-temperature butter until fluffy, then add powdered sugar, cocoa powder, and cooled melted chocolate to make the frosting.

Once cooled, assemble the cake by stacking and frosting the layers.