Preheat and Prep
Preheat the oven to 350°F (175°C). Grease two 9-inch round cake pans and line them with parchment paper.
Mix Dry Ingredients
In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt.
Add Wet Ingredients
Add eggs, buttermilk, oil, and vanilla extract. Mix until smooth.
Pour in Hot Coffee
Slowly add hot coffee while mixing. The batter will be thin—this is normal.
Bake the Cake
Divide the batter evenly between the cake pans. Bake for 30-35 minutes or until a toothpick comes out with a few moist crumbs. Let cool for 10 minutes before transferring to a wire rack.
Make the Frosting
Beat butter until creamy, then slowly mix in powdered sugar, cocoa powder, and salt. Add vanilla and heavy cream, mixing until fluffy.
Assemble and Frost
Spread frosting on one cake layer, stack the second layer, and frost the entire cake. Slice and enjoy.