1 c. mayonnaise
1 c. cold water
1 tsp. vanilla extract
2 c. all-purpose flour
1 c. sugar
1/2 c. cocoa
1 1/2 tsp. baking soda
9x13 inch pan, greased and floured

Preheat oven to 350 degrees. Mix together mayonnaise, water and vanilla extract until well combined. Sift together flour, sugar, cocoa and baking soda and add to mayonnaise mixture. Blend until smooth. Pour into prepared pan and bake for 35 minutes. Allow cake to cool before frosting.