Heat oven to 350ºF (325ºF for dark or nonstick pan).

Grease bottom only of 9-inch square pan with shortening or cooking spray.

In small bowl, beat all filling ingredients with electric mixer on low speed until smooth.

Set aside.

Make brownie batter as directed on box.

Spread three-fourths of batter in pan.

Spoon filling by tablespoonfuls evenly over batter.

Spoon remaining batter over filling.

Cut through layers with knife several times for marbled design.

Sprinkle with chocolate chips.

Bake 40 to 44 minutes or until toothpick inserted in brownie 1 inch from edge comes out almost clean.

Cool completely, about 1 hour 30 minutes.

Cut into 4 rows by 4 rows.

Store covered in refrigerator.