Patience Cake
["1 box Duncan Hines Butter Recipe cake mix", "2 (9 oz.) Cool Whip", "2 small cartons sour cream or 1 large carton", "1 box powdered sugar", "coconut and nuts (optional)"]
["Bake cake as directed and split each layer in half, making 4 layers.", "Mix remaining ingredients and spread on cooled cake. Refrigerate 3 days before cutting."]
["Butter", "sour cream", "powdered sugar", "coconut"]