Preheat the oven to 350 degrees. Line an 8×8" baking dish with parchment paper or foil.

Melt the butter in a medium sauce pan over low heat. Once melted, increase the heat to medium and add the 1 cup of sugar, cocoa powder and salt and stir to combine. Continue to cook, stirring often, until the mixture is very warm to the touch and most of the sugar has melted, about 2 minutes. Remove from heat and stir in the vanilla extract, and let stand 5-10 minutes, stirring occasionally to help cool the mixture down.

Add the eggs one at a time, stirring vigorously after each addition. Stir in the flour just until incorporated (about 30 strokes). Reserve 1/3 a cup of the batter and set aside, then stir in all but 2 tablespoons of the chocolate chips.

Pour the remaining batter into the prepared pan and spread evenly.

In a medium bowl, beat the cream cheese on medium speed with a hand mixer until smooth, about 2 minutes. Add the egg, sugar and vanilla and beat until incorporated.

Dollop the cream cheese mixture over the brownie layer in the pan in (9) large dollops. Dollop the reserved 1/3 cup brownie batter over the top of the cream cheese dollops, then using a knife, swirl the top of the brownies in a circular motion to create decorative swirls without going to the bottom of the pan. Top with the reserved 2 tablespoons of chocolate chips.

Bake at 350 degrees for 22-25 minutes, or until the brownies have puffed and the cheesecake has set but is still a bit wobbly. A toothpick inserted into the center should come out with moist crumbs. If the cheesecake topping begins to brown before the brownies are done, cover the pan loosely with foil for the remainder of the baking time.

Remove from heat and cool completely on a wire rack. Cut into squares and enjoy!