Potato Chocolate Cake
["2 1/2 c. flour (self-rising)", "1/2 c. milk", "3 c. sugar", "4 Tbsp. cocoa", "1 1/2 c. mashed potatoes", "2 sticks margarine", "4 eggs", "1 tsp. vanilla", "1/2 tsp. salt"]
["Mix dry ingredients well.", "Melt margarine, then mix all liquid ingredients.", "Add to dry ingredients.", "Mix well.", "Bake at 350\u00b0."]
["flour", "milk", "sugar", "cocoa", "potatoes", "margarine", "eggs", "vanilla", "salt"]