In the bowl of your mixer, add the flour, sugar, cocoa, baking soda, baking powder and salt. Using the paddle attachment mix everything until well combined on low speed. In a medium sized bowl, mix together the buttermilk, oil, eggs and vanilla. Add the wet ingredients to the dry ingredients and mix. With the mixer still on low speed, slowly add the coffee and continue mixing until everything is well combined. Scrape the bottom of the bowl with a spatula and mix as needed. Pour the batter into the 2 prepared pans, equally.
You will need 2 cake pans, each 8 inches in diameter. Cut out 2 parchment paper circles that will fit inside the cake pans. Place the parchment papers inside and using some melted butter, butter each pan well.