Preheat your oven to 350 degrees F and grease a 9 inch cake pan, set aside.
In a large bowl, mix together the chocolate cake mix with the oil, milk, egg and vanilla until well combined.
Fold in the chocolate chips until just mixed .
Spread the brownie cake mixture into the bottom of your greased cake pan, reserving 1 cup of the batter.
In a medium bowl, blend together the cream cheese, egg, sugar and vanilla extract until smooth.
Pour over the brownie batter in the cake pan.
Take your reserved cup of brownie batter and dot spoonfuls of the batter across the top of the cream cheese.
Using a knife or toothpick, swirl the batter into the cream cheese.
Place the cake pan into the preheated oven and bake for 20-25 minutes, or until a toothpick inserted in the center comes out clean.
Allow the cake to chill in the refrigerator for at least one hour. Slice the cake and serve, enjoy!