Preheat oven to 325 degrees. Spray a 15 x 10" baking pan with Baker's Joy or grease and flour it.
In a large bowl, combine cake mix, sour cream, half & half, eggs and oil. With an electric mixer on low speed, blend 30 seconds. On medium speed, beat for another 1 1/2 minutes. Pour batter into prepared pan. Bake for 22 minutes or until toothpick inserted in center comes out clean. Cool completely before frosting.
Frosting: In large bowl, beat cream cheese and butter until well blended. Gradually, add powdered sugar. Stir in vanilla and half & half. Spread frosting on cooled cake. Sprinkle with coconut. Cover and store in refrigerator.