Preheat your oven to 350°F (175°C) and grease and line two or three 8-inch cake pans.
In a large bowl, whisk together flour, cocoa powder, sugar, baking soda, baking powder, and salt.
Add eggs, buttermilk, vegetable oil, and vanilla extract. Beat until all ingredients are well combined.
Slowly pour in hot coffee, mixing until the batter is smooth. (Don’t worry, it’s supposed to be thin!)
Divide the batter evenly among the prepared pans and bake for 28-32 minutes, or until a toothpick inserted into the center comes out clean.
Allow cakes to cool in the pans for 10 minutes before transferring to wire racks to cool completely.