Preheat your oven according to package directions. Prepare brownie mix according to package directions and set aside.
In a medium sized bowl, beat your cream cheese for a couple minutes until smooth.
Add in the peanut butter and cream together till smooth.
Add in your sugar, egg, flour and vanilla extract and stir till combined.
Pour all but 1/2 cup of your brownie batter into a 9x13 pan sprayed with nonstick spray.
Spoon the cream cheese mixture on top of the brownie batter.
Spoon the remaining brownie batter on top of the cheesecake mixture.
Use a knife to swirl the cream cheese and brownie batter together to create a marbled effect.
Bake in preheated oven for 35-40 minutes or until a toothpick inserted near the middle comes out clean.
Remove from oven and allow cool before cutting into pieces