PREPARATION:

1. Preheat oven to 350°F. Line 18 standard (2-1/2-inch) muffin pan cups with paper muffin cup liners. Prepare brownie mix according to package directions for cakelike brownies. Stir in chocolate chips. Spoon batter into prepared muffin pans, dividing evenly.
2. Combine cream cheese and egg in small bowl; beat until well combined. Add sugar, flour and vanilla; beat until well combined.
3. Place cream cheese mixture in resealable food storage bag; seal bag. With scissors, snip off small corner from one side of bag. Pipe cream cheese mixture in concentric circle design on each cupcake; draw toothpick through cream cheese mixture, out from center, 6 to 8 times.
4. Bake 20 to 25 minutes or until toothpick inserted into centers comes out clean. Cool in pans on wire racks 15 minutes. Remove to racks; cool completely.