Spray an 8" springform pan lightly with cooking spray. Prepare the brownies according to the package directions. Instead of using a brownie pan, pour them into the prepared cheesecake pan and (again) bake them according to the package directions.

When the brownies have completely cooled, prepare the cheesecake filling. In a small bow add chocolate chips and heat in microwave for 1-minute. Stir, and then heat in 30 second intervals stirring in between until chocolate is completely smooth and melted. Or melt them using a double boiler. Set aside to cool.

In the bowl of a stand mixer, beat together the cream cheese, sugar and butter until smooth and creamy. While the mixer continues to run, slowly pour in the cooled melted chocolate chips, continuing to slowly stir until they're evenly incorporated. Use a firm spatula to gently fold in the cool whip until the mixture's smooth.

Use a spatula to gently stir in the chocolate chips until they're just spread throughout the batter. Spread the cheesecake batter out on top of the cooled brownies.

Place the cheesecake in the refrigerator until set, or about an hour.

Before serving spread a layer of hot fudge out over the top of the chilled cheesecake.