1 c. sugar
1 c. butter
1 c. warm water
1 tsp. vanilla
2 c. flour
2 tsp. baking soda
1/2 tsp. cream of tartar
4 tbsp. cocoa

Mix sugar, mayonnaise and water together. Add vanilla. In a separate bowl sift together flour, baking soda, cream of tartar and cocoa. Mix with mayonnaise mixture and beat until smooth. Pour into greased 13x9 inch pan and bake at 350 degrees for 35 minutes.