Mayonnaise Cake

2 cups flour
2 cups sugar
3 eggs
5 Tbsp. cocoa
1 cup cold water
2 tsp. soda
1 tsp. salt
1 tsp. vanilla
1 cup mayo

Beat eggs, sugar, mayo, vanilla and water. Add rest of ingredients. Beat for 3 min. Bake @350 for 40-50 min. 20 min. if jelly roll.