Preheat oven to 350°F.

Grease and flour a 9 X 13 inch pan, two 9 inch round pans, or three 8 inch round pans and set aside.

In a mixing bowl, cream together the butter and the sugar until fluffy.

Add the eggs and beat well.

Alternate adding the buttermilk and the flour.

Add the baking soda, cocoa, vanilla and salt.

Mix well.

Pour into the pan(s) and bake for 40 to 50 minutes for a 9 X 13 pan or 20 to 25 minutes for the round pans.

The cake is done when the center springs back when touched.

Let cool completely before frosting.