Chocolate Mayonnaise Cake

Why I Love This Recipe
I got this recipe off of a yahoo menu group.
My 15 yr old son devours this in one day....I can't figure out why he doesn't gain ONE POUND? LOL
Ingredients You'll Need
2 Cups Flour
1/2 Cup Cocoa
1 1/2 tsp Baking Soda
1/4 tsp Salt
1 Cup Sugar
3/4 Cup Mayonnaise
1 Cup Water
1 tsp Vanilla
Directions
Sift together the flour, cocoa, soda and salt. Cream together the sugar, mayonnaise, water, and vanilla.
Add dry ingredients to the creamed mixture; stir until well blended.
Pour batter into greased and floured layer cake pans (or a 9 x 13-inch pan).
Bake 350 degrees F for about 25 minutes.
Let cool completely on wire rack before frosting if desired.