Combine flour, sugar, cocoa, baking soda and salt in large bowl. Add water, oil, vinegar and vanilla; stir with spoon or wire whisk just until batter is smooth and ingredients are well blended.
Pour into greased and floured 9-inch layer pan or 8-inch square pan. Bake at 350 for 35-40 minutes or until tester comes out clean. Cool in pan; frost as desired (I made a buttercream frosting recipe off a confectioner's sugar box which tasted really good with the cake.)
