Mix flour, sugar, baking soda, salt and cocoa powder in one bowl.
Mix all the wet ingredients in another bowl.
Mix the two bowls together.
Bake at 350 until cooked or a toothpick comes out dry.
I did two 10 inch pans today, and it took about 50 minutes. I would bake it for a normal cake recipe time (30-35 minutes) and then watch carefully from there.
I make my own buttermilk. It seems more moist when I do it that way. I am sorry for those instructions. I got this recipe from a friend who also does a lot of cakes. I have made it a few times but never wrote down the time.