PREPARE cake batter and bake as directed on package for 2 (9-inch) round cake layers. Cool cakes in pans 10 min. Invert onto wire racks; gently remove pans. Cool cakes completely. Meanwhile, toss berries with sugar. Refrigerate 30 min.
WRAP 1 cake in foil; freeze for another use. Cut remaining cake horizontally in half; spread bottom layer with jam. Top with remaining cake layer. Use 2-1/2-inch cookie cutter to cut circle from center of cake; set aside. Cut remaining cake into 2-inch pieces.
BEAT pudding mix and milk in medium bowl with whisk 2 min. Stir in COOL WHIP.
LAYER half each of the cake pieces, berries (with juices) and pudding mixture in large glass bowl; repeat layers. Top with reserved cake round. Refrigerate 4 hours.