Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment paper so that it hangs over two of the sides then grease it with cooking spray.
In a medium bowl, stir together the crushed graham crackers and melted butter. Transfer the mixture into the prepared pan and press it firmly into an even layer.
In the bowl of a stand mixer fitted with the paddle attachment, beat together the cream cheese, sugar and vanilla extract until well combined. Add the eggs one at a time, beating between each addition.
Transfer 1 cup of the cheesecake mixture to a separate medium bowl then whisk in the pumpkin purée and pumpkin pie spice.
Alternately add scoops of the plain cheesecake and pumpkin cheesecake fillings on top of the crust. Using a sharp knife or toothpick, swirl the batters together.
Bake the cheesecake for 20 to 25 minutes until the center is almost set.
Remove the pan from the oven and let the cheesecake cool completely before covering the pan with plastic wrap and refrigerating it for a minimum of 3 hours and up to overnight.
Remove the cheesecake from the fridge, slice it into bars and serve with whipped cream (optional).