Potato Cake (Chocolate)
["1/2 c. buttermilk", "1 c. mashed potatoes", "1 tsp. vanilla", "1 3/4 c. flour", "2 tsp. baking powder", "2 egg whites, beaten", "2/3 c. shortening", "2 c. sugar", "4 egg yolks, well beaten", "2 sq. melted chocolate*", "1/2 tsp. salt", "1 c. walnuts"]
["*Put chocolate squares in oven or microwave to melt."]
["buttermilk", "potatoes", "vanilla", "flour", "baking powder", "egg whites", "shortening", "sugar", "egg yolks", "chocolate", "salt", "walnuts"]