Twelve O' Clock Chocolate Cake

2 cups flour sifted
1 tsp. baking powder
1 tsp. baking soda
1/2 tsp. salt
1 cup sugar
1/3 cup cocoa unsweetened
1 cup water
3/4 cup mayonnaise
1 tsp. vanilla
Grease and flour 13 by 9 by 2 pan. Sift dry ingredients in a 
mixing bowl. Add water, mayonnaise and vanilla. Blend with an 
electric mixer until smooth. Pour into prepared pan. Bake at 350 
degrees for 30-35 minutes or until toothpick comes out clean. 
Cool completely. Frost if desired.