Preheat oven to 325F/160C.
Grease and flour 2 x 6 inch round baking tin.
Sift together flour, salt, baking powder, baking soda, and cocoa powder.
In your mixer, beat sugar and oil until combined.
In another bowl, beat in egg, buttermilk, vanilla, and red food colouring.
Then add in coffee, and white vinegar.
Add 1/3 of the flour mixture into mixer bowl, then 1/3 of the buttermilk mixture.
Allow to mix after each addition.
Alternate until done, and just combined.
Divide batter into the 2 prepared baking tins.
Bake in middle rack for 30-40 minutes, or until skewer inserted comes out clean.
Allow to cool in pan for 5 minutes before de-moulding.
Cool completely on wire rack before frosting.