Prepare brownie mix as directed on package.
Pour into greased 13x9" baking pan.
Beat cream cheese with electric mixer
on medium speed until smooth.
Add sugar, mixing until blended.
Add egg and vanilla; mix just until blended.
Pour cream cheese mixture over brownie mixture;
cut through batter with knife several times for marbled effect.
Bake at 350F for 35-40 minutes or until
cream cheese mixture is lightly browned.
Cool; cut into squares.