1 (18 1/2 oz.) pkg. butter flavor 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 the directions on the box, making two 8-inch layers. When completely cooled, split both layers in half.

Combine sugar, sour cream and coconut, blending well. Chill. Reserve 1 cup sour cream mixture for frosting; spread the 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.