Grease 9 x 9 x 2 inch baking pan, line bottom with wax paper. Grease paper.

Mix and sift flour, sugar, cocoa, baking powder and baking soda into large mix-

ing bowl. Stir in mayonnaise. Gradually stir in water and vanilla until smooth

and blended. Pour into pan. Bake at 350 degrees for 40 to 45 minutes or until

done. Cool.