Grease and line a rectangular baking tin with parchment paper leaving an overhang sp it is easier to remove them from the pan once cooked.
Preheat the oven to 375f.
Start with the brownie base by mixing together the eggs and sugar before adding in the melted butter and chocolate.
Stir in the flour until just combined then pour three quarters of the batter into the base of the lined baking tin. Spread out in an even layer.
Now make the cheesecake by mixing together the eggs and the sugar. Add in the vanilla and mix again before finally mixing in the softened cream cheese.
Pour the cheesecake mixture over the layer of brownie batter in the baking tin and spread to cover in an even layer.
Drop spoonfuls of the reserved brownie batter into the cheesecake mixture and using a toothpick, make swirls in the cheesecake batter.
Scatter on the chocolate chips then place into the oven to bake for around 25-30 minutes.
Allow to cool in the baking tin then turn out onto a board and slice into bars.