Luscious Coconut Cake
["1 box Duncan Hines cake mix (with butter)", "1 c. sugar", "1 (8 oz.) carton sour cream", "3 (12 oz.) pkg. frozen coconut, thawed", "1 (8 oz.) carton Cool Whip"]
["Prepare cake mix according to directions, making two 9-inch layers.", "When completely cool, split both layers.", "Combine sugar, sour cream and coconut; blend well and chill.", "Reserve one cup of this mixture for frosting and spread remainder between layers. Combine reserved sour cream mixture with Cool Whip.", "Blend until smooth.", "Spread on top and sides.", "Seal cake in airtight container in refrigerator.", "(I make this cake at least 3 days ahead of time, just makes it better.)"]
["cake", "sugar", "sour cream", "frozen coconut"]