Preheat the oven to 325 degrees F and lightly grease a 9" Springform pan or line with parchment paper. Wrap a large piece of tin foil around the bottom and partially up the sides of the pan.
In a medium bowl, combine graham cracker crumbs and melted butter. Press into the prepared pan and up the sides about 1 inch up the sides. Bake for 12-15 minutes or until firm and no longer moist.
When done, reduce the oven heat to 275 degrees F.
Meanwhile, prepare your filling. In a large bowl, beat cream cheese until smooth. Add sugar and beat until combined.
Add pumpkin, eggs, vanilla and pumpkin pie spice and beat on low until combined -- you don't want to incorporate too much air into the cheesecake.
Pour into crust and smooth the top. Bake at 275 degrees F for 1 hour 15 minutes to 1 hour 30 minutes, or until the outer 2 inches are set but the center is still slightly jiggly.
Turn off the oven and let sit in the warm oven for 1 hour.
Remove from the oven and let sit for 15 minutes before carefully running a knife around the edge of the pan to loosen the cheesecake. Let cool to room temperature before chilling in the fridge completely (overnight is best!), then remove from the pan and serve with whipped cream.