Preheat & Prepare:
Preheat your oven to 350°F (175°C). Grease and line two 9-inch (23cm) round cake pans with parchment paper.

Mix Dry Ingredients:
In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt.

Combine Wet Ingredients:
In another bowl, whisk together buttermilk, oil, eggs, and vanilla extract until smooth.

Mix the Batter:
Gradually add the wet ingredients to the dry ingredients, stirring until just combined. Then, slowly mix in the hot coffee (batter will be thin).

Bake the Cake:
Divide the batter evenly between the prepared pans and bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean. Let the cakes cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

Make the Ganache:
Heat the heavy cream in a saucepan over medium heat until it just starts to simmer. Pour over the chopped chocolate and let sit for 5 minutes. Stir until smooth, then mix in butter and vanilla. Let it cool until thickened but still spreadable.

Assemble & Frost:
Place one cake layer on a serving plate. Spread a layer of ganache over the top. Place the second cake layer on top and cover the entire cake with ganache.

Chill & Serve:
Let the cake set for about 30 minutes before slicing. Serve and enjoy!