Water, vegetable oil and egg called for on brownie mix box
Heat oven to 350°F (325°F for dark or nonstick pan). Grease bottom only of 9-inch square pan with shortening or cooking spray. In small bowl, beat filling ingredients with electric mixer on low speed until smooth. Set aside.
2Make brownie batter as directed on box. Spread 3/4 of brownie batter in pan. Spoon filling by tablespoonfuls evenly onto brownie batter. Spoon remaining brownie batter over filling. For marbled design, pull knife through batter and filling in wide curves; turn pan and repeat, if desired.
3Bake 40 to 44 minutes or until toothpick inserted 1 inch from side of pan comes out almost clean. Cool completely at room temperature, about 1 1/2 hours. Refrigerate at least 1 hour until chilled. For brownies, cut with plastic knife into 4 rows by 4 rows. Store covered in refrigerator.