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, thawed

Prepare cake mix according to package directions, making two 8 inch layers. When 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 airtight container and refrigerate for 3 days before serving.