MIX cake mix, butter, eggs and vanilla until well blended. Press evenly into bottoms of 8 (6-inch) cake pans (or 4 cake pans for trial recipe). Top each with 1/2 cup Cheesecake Batter, spreading evenly.
BAKE in 350ºF standard oven 12 to 15 min. or until centers are set. Cool completely. Unmold cakes.
DUST each cake with 1 tsp. powdered sugar; cut into 4 slices. Serve 4 slices with 1/4 cup berries.