1 (18 1/2 oz.) pkg. butter flavored cake mix
1 (8 oz.) carton sour cream
12 oz. frozen coconut, thawed
1 1/2 c. Cool Whip
2 c. sugar

Prepare cake according to directions on package, making two 8 inch layers. Let cool. Split both layers horizontally. Blend together sugar, sour cream, and coconut. Chill.

Spread all but 1 cup of sour cream mixture between the four layers. Blend remaining cup of mixture with Cool Whip and spread on top and sides of cake. Seal in an airtight container and refrigerate for 3 days before serving. Keep refrigerated after cutting.