Preheat oven to 350 F degrees.

Prepare the brownie mix according to package directions (water, oil, eggs). Pour into a greased 13x9-inch baking pan.

Beat the cream cheese with an electric mixer on medium speed until smooth.

Add the sugar and mix. Add the vanilla and egg; mix until well-blended.

Place the cheese mixture in spoon fulls over the whole pan, leaving some brownie showing in between.

Cut or swirl through the batter several times with a knife or fork for a marbled effect. It can be tricky to get a good marble effect so be careful not to over work it.

Bake for 35 to 40 minutes. Cool; cut into squares.