Preheat the oven to 350°.
Grease and flour your two 9" cake pans, or grease and line with parchment paper circles.
In your mixer, add the flour, sugar, cocoa powder, baking soda, and salt and mix until combined.
Add the eggs, melted butter, vanilla, and buttermilk, and mix until just combined.
Remove the bowl from the mixer and stir the hot coffee into the batter by hand. The batter will be runny. It’s supposed to be.
Pour into your cake pans and bake until a toothpick inserted into the center comes out clean with just a few bits of cake stuck to it. For my 3 layers in 7 inch pans, that was about 15 minutes. For 9 inch pans, that should be anywhere from 20-30 minutes. Start checking around 15 minutes.
When you remove each cake from the oven, let it cool for 5 minutes, then run a knife around the edges of the pan, and carefully tip the pan over on a cooling rack.
If you used parchment on the bottom you can remove it. Let cakes cool completely before frosting.