Preheat oven to 350º Line an 8-9 inch square pan with parchment paper, leaving an overhang of parchment on both sides. Coat the parchment lined pan with cooking spray.
For the brownies, place the butter and 1 1/3 cups of the chocolate chips into a large bowl. Microwave in 30 second increments until just melted. Stir until smooth.
Let chocolate mixture cool for 5 minutes. Whisk in the sugar, whisk in the eggs one at a time, and finally whisk in the vanilla extract
Add the flour, cocoa powder, and salt to the bowl. Stir gently until just combined.
Reserve 1/4 of the brownie batter in a separate bowl
Fold in remaining chocolate chips into the larger amount of brownie batter.
Spread the larger amount of batter evenly onto the prepared pan.
For Cheesecake mixture: Place cream cheese and sugar in a bowl. Beat with mixer for 2-3 minutes or until smooth and creamy. Add egg and vanilla extract, beat again until smooth.
Pour the cheesecake mixture over the brownie batter in the pan
Add 1 tablespoon of very hot water to the reserved brownie batter. Stir until smooth
Dollop the brownie batter over the cheesecake topping. Use a skewer or knife to swirl the two batters together.
Bake for 30-35 minutes or until toothpick inserted into the center of the brownie comes out clean or with just a few crumbs attached
Cool brownies completely, use parchment overhang to life the brownies out of pan. Cut into squares, then serve