This is my favorite way to make a regular old brownie mix more special.
Prepare 1 package of regular fudge brownie mix according to the directions on the box. Spread brownie mix in the bottom of a 9 x 13" pan.
Beat together the following ingredients in a bowl until smooth:
1 package of cream cheese (room temperature)
1/2 tsp vanilla
1/2 c sugar
Add spoonfuls of cheesecake mixture to brownies. With a knife, make swirls in the mixture. Bake at 350 degrees for about 30 minutes.