HEAT oven to 350ºF.
PREPARE cake batter, in 2-1/2-qt. ovenproof bowl sprayed with cooking spray, as directed on package; scrape side of bowl. Add dry gelatin mix and 1/4 cup milk; beat until blended.
BAKE 55 min. or until toothpick inserted in center comes out clean. Cool cake in bowl 10 min. Loosen cake from side of bowl with knife; invert onto wire rack. Remove bowl. Cool cake completely.
MEANWHILE, beat dry pudding mix, sugar and remaining milk in medium bowl with whisk 2 min. Stir in COOL WHIP. Refrigerate until ready to use.
PLACE cake, flat side down, on plate; frost with pudding mixture. Cover with coconut.