1 box yellow cake mix
2 c. sugar
12 oz. frozen coconut, thawed
1 (16 oz.) sour cream

Bake cake mix in 2 layers. Chill and split layers. Mix sugar, coconut, and sour cream and let stand. Reserve one cup. Spread the rest between the layers of cake. Add the reserved 1 cup to 1 carton Cool Whip. Frost cake with this mixture. Refrigerate overnight.