Mayonnaise Cake
["2 c. flour", "1 c. sugar", "2 tsp. soda", "4 Tbsp. cocoa", "1 c. mayonnaise", "1 c. water", "1 tsp. vanilla"]
["Sift dry ingredients together, then add mayonnaise and water. Mix only enough for a smooth batter.", "Do not beat.", "Bake in greased 9 x 9-inch pan.", "Bake at 350\u00b0 until toothpick inserted in center comes out clean.", "Let cool.", "Frost with peanut butter frosting."]
["flour", "sugar", "soda", "cocoa", "mayonnaise", "water", "vanilla"]