1 (20.5-ounce) package brownie mix
1 (8-ounce) package cream cheese, softened
1/3 cup granulated sugar
1 large egg
1/2 teaspoon vanilla extract
1/2 cup semisweet chocolate chips
Prepare brownie mix as directed on package; spread into a greased 13×9-inch baking pan.
In a bowl, with an electric mixer at medium speed, beat cream cheese until smooth. Add sugar, mixing until smooth. Add egg and vanilla; mix just until blended.
Pour cream cheese mixture over brownie mixture; cut through batter with knife several times for marble effect. Sprinkle with chocolate chips.
Bake at 350°F for 35 to 40 minutes or until cream cheese mixture is lightly browned. Cool; cut into squares.
Makes 18 bars.