Preheat oven to 300 F
Butter three 8-inch cake pans
Add flour, sugar, cocoa powder & salt to a mixing bowl- combine well.
To dry ingredients, add eggs, buttermilk, vegetable oil, and vanilla extract- mix well.
Add in hot coffee and combine until all ingredients are incorporated
Divide batter evenly between pans and bake for 30 minutes. Check around 25 minutes because some ovens cook quicker.
Remove cakes, allow to cool for 15 minutes, then transfer to cooling racks and let rest until completely cool.
While the cakes are cooling, make the frosting by beating the butter in a mixing bowl until smooth.
Add in powdered sugar 1 cup at a time to ensure you don't make the frosting too dry.
Add in vanilla extract, milk, and cocoa powder. Mix for 5 minutes until the frosting is smooth. Add in more milk if the frosting is too thick or more powdered sugar/cocoa powder if the frosting is too thin.
Frost cake and enjoy :)