1 (18 1/2 oz.) pkg. butter cake mix
2 c. sugar
1 (16 oz.) carton sour cream
1 1/2 c. frozen whipped topping, thawed
1 (12 oz.) pkg. frozen coconut, thawed
1 (6 oz.) pkg. frozen coconut, thawed

Prepare cake mix according to package directions, making two 8 inch layers. When completely cooled, split both layers. Combine sugar, sour cream, and 12 ounce package of coconut, blending well. Chill. Reserve 1 cup sour cream mixture for frosting. Spread remainder between layers of cake. Stack layers split side up.

Combine reserved sour cream mixture with whipped topping; blend until smooth. Spread on top and sides of cake. Sprinkle with 6 ounce package of coconut. Seal cake in an airtight container and refrigerate 3 days before serving.