Preheat oven to 350°F and line a 9×13 metal pan with foil, greasing it lightly.
Pulse graham crackers into fine crumbs, combine with 2 tablespoons of sugar and melted butter, then press firmly into the prepared pan.
Bake the crust for 10 minutes and let cool slightly.
In a medium bowl, whisk together pumpkin puree, 1/2 cup sugar, pumpkin pie spice, cinnamon, and flour until smooth.
In a large bowl, beat cream cheese with remaining sugar, vanilla, and salt until light and fluffy.
Add eggs one at a time, followed by sour cream, beating until smooth.
Spread two-thirds of the cheesecake mixture over the crust.
Drop dollops of the pumpkin mixture and remaining cheesecake mixture on top, then swirl with a knife to create a marbled effect.
Bake for 40-50 minutes until the center is just set.
Cool to room temperature, then refrigerate for at least 4 hours before slicing into 16 bars.