Preheat Oven: Preheat your oven to 350°F (177°C). Grease and flour three 6-inch or two 8-inch round cake pan.

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

Add the eggs one at a time to the dry ingredients, mixing well after each addition.

Add the buttermilk, oil, melted butter, and vanilla extract to the bowl. Mix until the batter is well combined.

Slowly pour in the hot brewed coffee, mixing gently until it’s fully incorporated. The batter will be thin, which is normal.

Pour the batter evenly into the prepared cake pans. 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 them to a wire rack to cool completely before frosting.

Heat the heavy cream in a small saucepan (or microwave) until steaming (do not boil).

Combine the cocoa powder and chopped chocolate in a heatproof bowl. Pour the hot cream over the chocolate and let it sit for 1 minute. Whisk until fully melted and smooth. Set aside and allow the mixture to cool to room temperature.

In a stand mixer or large bowl using a hand mixer, beat the butter on medium-high speed for 3–4 minutes, until pale, creamy, and fluffy.

With the mixer on low speed, gradually add the cooled chocolate mixture to the whipped butter.

Once incorporated, increase speed to medium-high and beat for 2–3 minutes, until the frosting lightens in color and becomes fluffy and smooth.

Add the powdered sugar, salt, and vanilla.

Beat on low until combined, then on medium-high for 1–2 minutes until fully whipped and glossy. If the frosting is too thin, refrigerate it for 15 minutes, then beat again. Frost onto your cake and enjoy!