Preheat oven to 350. Mix dry ingredients together in a 8x8 pan or 10" cast iron skillet. Make three wells in the dry ingredients; pour the oil into one; vinegar in the second; vanilla in the third. Pour cold water over entire pan. Stir with a fork until well blended.
Bake at 350 for 25 minutes. Frost.
Frosting: cream powdered sugar and cocoa together with butter. Add coffee (or milk) and mix well. Spread over the cooled cake.