Prize Pinto Bean Cake

1-3/4 cups flour
1 cup sugar
2 teaspoons baking soda
1 cup mayonnaise
1/4 cup water
1 cup mashed pinto beans
1 teaspoon allspice
1 teaspoon vanilla
1/2 teaspoon cinnamon
1/2 teaspoon nutmeg

Combine dry ingredients. Add mayonnaise, water, and beans. Mix well. Bake in greased 9x13-inch rectangular pan at 350 degrees for 35 to 40 minutes. When cool, frost with a light caramel frosting.

(Source: W. Thueson)