Preheat oven to 180℃ / 350℉.
Line a square baking pan (roughly 8 x 8inches) with baking paper.
Melt butter in the microwave in a large, microwave safe bowl.
Add the rest of the brownie ingredients one at a time in the order listed in the ingredients section.
Stir the mixture after each addition.
Pour ¾ of the brownie batter into the prepared tin.
Use an electric mixer to blend together the cheesecake ingredients, blend until smooth.
Spread the cheesecake mixture on top of the raw brownie batter.
Dollop the remaining brownie batter on top of the cheesecake mixture.
Use a skewer or a knife to swirl the mixtures together and create the marbled effect.
Bake for 30 minutes.
Allow to cool completely before cutting and enjoying.