This recipe is from Shirley McNevich's Mom's Best Recipes Vol 1. Published here with her permission.
Don't forget to check Shirley's blog.
(by Shirley McNevich)
1 box chocolate cake mix (Duncan Hines)
1 cup Hellmann's mayo
1 cup cool tap water
Put all ingredients in mixer and blend well--beat until smooth. Pour batter in a 9 x 13 x 2 greased cake pan (or two greased layer cake pans). Bake at 350 degrees for 30-35 minutes. Test with a toothpick for doneness. Use our frosting recipe #2 to make vanilla or chocolate frosting (your preference).