Preheat the oven to 325°F (165°C).
Line a 9 × 9-inch baking pan with parchment paper, leaving overhang on two sides.
Combine the graham cracker crumbs, melted butter, brown sugar, and cinnamon.
Press the crumb mixture firmly and evenly into the bottom of the prepared pan.
Bake the crust for 8 minutes, then remove it from the oven and allow it to cool slightly.
Beat the softened cream cheese on medium-low speed until completely smooth.
Add the granulated sugar and mix just until combined.
Add the sour cream, vanilla extract, and salt and mix until smooth.
Add the eggs one at a time, mixing on low speed only until incorporated.
Transfer approximately 1 1/4 cups of the cheesecake mixture to a separate bowl and reserve.
Add the pumpkin puree, brown sugar, pumpkin pie spice, and cinnamon to the cheesecake mixture remaining in the large bowl.
Mix on low speed just until evenly combined.
Spread most of the pumpkin cheesecake mixture over the prepared crust.
Drop spoonfuls of the reserved vanilla cheesecake mixture across the pumpkin layer.
Spoon small amounts of the remaining pumpkin mixture between the vanilla dollops.
Use a butter knife or thin skewer to gently create several loose swirls through the two fillings.
Bake for 40–45 minutes, until the edges are set and the center retains a slight wobble.
Turn off the oven, crack the door slightly, and leave the cheesecake inside for 15 minutes.
Remove from the oven and cool completely at room temperature.
Cover and refrigerate for at least 4 hours, preferably overnight.
Lift the chilled cheesecake from the pan using the parchment paper.
Cut into 16 bars with a sharp knife, wiping the blade clean between cuts.