Step 1: Get Everything Ready

1. Preheat the oven to 350°F (175°C).
2. Grease and flour, or line with parchment paper, two 8-inch round cake pans.

Step 2: Combine the Dry Ingredients

1. In a large bowl, sift the flour, cocoa powder, baking powder, baking soda and salt. Sifting helps create a lump-free, fluffy cake.

Step 3: Blend the Wet Ingredients

1. With a hand or stand mixer, beat the granulated sugar, brown sugar, eggs, and vegetable oil together until light and fluffy (about 2 minutes).
2. Mix in the vanilla extract and buttermilk until just combined.

Step 4: Combine & Add Coffee.

1. Gradually add the dry ingredients into the wet mixture in small increments, mixing gently to avoid overmixing.
2. Just add the hot coffee at the end. The batter will be thin — don’t be alarmed, it’s supposed to be! The coffee deepens the chocolate flavor and helps the cake stay moist.

Step 5: Bake the Cake

1. Pour the batter evenly between the prepared pans.
2. Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted into the center comes out clean. 
3. Let the cakes cool in the pans for 10 minutes then turn onto a rack to cool.

Step 6: Prepare the Belgian Chocolate Ganache 

1. In a small saucepan, heat the heavy cream until it just begins to simmer (do not boil).
2. In a different bowl, pour the hot cream over the chopped Belgian dark chocolate. Let it sit for 2 minutes.
3. Stir until you have a smooth, glossy ganache. Add the butter if desired.

Step 7: Assemble and Frost

1. After the cakes cool completely, slather a thick layer of ganache between the two layers.
2. Pour the remaining ganache all over the cake to cover completely, then use a spatula to smooth and give it a polished finish.