• Preheat oven to 375 degrees. Butter and flour two round cake pans or spray with baking spray. I like to use a round piece of parchment paper on the bottom of the pan to ensure it doesn't stick. I butter and flour the parchment paper and sides of the cake pan.
• In the bowl of your stand mixer or in a large mixing bowl combine flour, sugar, baking soda, baking powder, salt, and cocoa. Whisk or stir together very well until it is completely mixed together.
• In a separate medium bowl combine the buttermilk, oil, eggs, and vanilla.
• If you are using a stand mixer, keep it running on low and slowly add the wet ingredients to the dry ingredients.
• Keep your mixer on low and slowly add the hot coffee. Be careful with this step because the coffee can splash. Mix until completely incorporated, stop half way and scrape the bottom of the bowl with a spatula and then mix again.
• Pour batter into prepared cake pans and bake 25-35 minutes or until a toothpick comes out clean. Cool in the pans for 20-30 minutes and then turn the cakes out of the pans on parchment paper to cool completely.

Make the frosting

• Melt the chocolate on very low heat and set aside to cool to room temperature. This is very important, do not add the chocolate if it is warm as it will melt the butter.
• Cream the butter on medium/high speed about 2 minutes until light and fluffy.
• Add the egg yolk and vanilla, mix for 2 minutes.
• On low speed, add the cooled chocolate and mix until completely incorporated.
• Spread on the cooled cake layers.