Sift flour, sugar, cocoa, baking soda and salt directly into 8" square cake pan. Make 3 holes/wells in the dry ingredients. In the first hole, pour vanilla; pour vegetable oil in one and in the last well, pour vinegar. Pour 1 cup cold water over all and stir with a fork until smooth. Bake at 350 degrees for 25 to 30 minutes
Cool on wire rack. Eat it plain; dust with powdered sugar or frost.