1. Preheat your oven to 350 F (175 C). Line a 9×13 inch baking pan with parchment paper, leaving an overhang on the sides to easily lift the brownies out later. Prepare the brownie mix according to the package directions in a large bowl. Pour about two-thirds of the brownie batter into the prepared pan and spread it evenly. Reserve the remaining one-third of the batter for later.

2. In a separate medium bowl, combine the softened cream cheese, granulated sugar, large egg, and vanilla extract. Beat with an electric mixer on medium speed until the mixture is smooth and creamy, with no lumps. This usually takes about 2-3 minutes.

3. Gently fold in the pumpkin puree and pumpkin pie spice into the cream cheese mixture until just combined. Be careful not to overmix at this stage; you want to maintain the creamy texture.

4. Carefully spread the pumpkin cheesecake mixture over the brownie batter in the pan. Try to spread it as evenly as possible without disturbing the brownie layer too much.

5. Dollop the reserved one-third of brownie batter over the pumpkin cheesecake layer. Use a knife or a skewer to gently swirl the brownie batter and pumpkin cheesecake mixture together. Don’t overdo the swirling; a few gentle passes are enough to create beautiful marbled patterns.

6. Place the pan in the preheated oven and bake for 30-35 minutes, or until the edges are set and the center of the cheesecake swirl appears mostly firm. A toothpick inserted into the brownie portion (not the cheesecake) should come out with moist crumbs, not wet batter.

7. Remove the pan from the oven and let the brownies cool completely on a wire rack. This step is vital for the cheesecake layer to set properly and for the brownies to achieve their ideal fudgy texture. Cooling can take 1-2 hours.

8. Once fully cooled, use the parchment paper overhang to lift the entire slab of brownies out of the pan. Place on a cutting board and slice into squares. Serve and enjoy!