In separate bowl, beat 4 oz cream cheese until smooth.
Add 1 egg, 3 T sugar and 1/4 tsp vanilla.
Spread 3/4 of the brownie mix in 9x9 square pan. Spread cream cheese mixture evenly over top. Add spoonfuls of remaining brownie mix on top. Cut knife back and forth through brownies (to swirl brownie and cream cheese mixture).
Bake 350 degrees for 45-50 mins, until toothpick inserted in brownie 1-inch from edge comes out "mostly" clean.