1 (18 1/2 oz.) pkg. butter-flavored cake mix
2 c. sugar
1 (16 oz.) carton sour cream
1 (12 oz.) pkg. frozen coconut, thawed
1 1/2 c. frozen whipped topping

Prepare cake mix according to directions, making two 8-inch layers; when completely cool, split both layers.

Combine sugar, sour cream, and coconut, blend well. Chill. Reserve 1 cup sour cream mixture for frosting; spread remainder between layers of cake. Combine reserved sour cream mixture with whipped topping; blend until smooth. Spread on top and sides of cake. Seal cake in an airtight container, and refrigerate for 3 days before serving.