1 pkg. Duncan Hines butter flavored cake mix, baked according to directions
2 c. sugar
1 (16 oz.) carton sour cream
1 (12 oz.) pkg. frozen coconut, thawed (fresh may be used)
2 c. frozen whipped topping, thawed

Slice the two layers of cake horizontally making a total of four layers. Combine sugar, sour cream and coconut, blending well. Chill. Reserve 1 cup mixture for frosting. Spread remainder between three layers of cake. Combine reserved mixture with whipped topping, blend until smooth. Spread on top and sides of cake. Seal cake in an airtight container and refrigerate for three days for full flavor.