Preheat oven to 350. Grease and flour 2-9 inch baking pans or line with parchment paper circles and set aside.
In a large bowl of a standing mixer stir together flour, sugar, cocoa, baking soda and salt.
Add eggs, buttermilk, melted butter and vanilla extract and beat until smooth about 3 minutes.
Remove bowl from mixer and stir in hot coffee with a rubber spatula. Batter will be very runny.
Pour batter evenly between the 2 pans and bake on the middle rack of oven for 35 minutes or until toothpick inserted in center comes out clean with just a few moist crumbs attached.
Allow to cool 15 minutes in pans then run a butter knife around the edges of each cake. Place a wire cooling rack over top of each pan.
Wearing oven mitts use both hands to hold the racks in place while flipping the cakes over onto the racks.
Set the racks down and gently thump on the bottom of the pans until the cakes release. Cool completely before handling or frosting.
I did not record the measurements for the icing. It is simply softened butter beaten with unsweetened cocoa powder, icing sugar, a pinch of salt, vanilla extract and a splash of cream adjusting the ingredients until i got the right consistency and sweetness.