Stir the graham cracker crumbs, sugar, pumpkin pie spice, and melted butter together. Press firmly into a 9-inch springform pan and par-bake at 350°F for 8 minutes. Let cool.
Make the Filling
Beat the room-temperature cream cheese with both sugars until completely smooth. Mix in the pumpkin, sour cream, pumpkin pie spice, vanilla, and salt.
Add the beaten eggs and mix on low just until combined. Do not overmix, as extra air causes cracks.
Bake and Chill
Pour the filling over the cooled crust. Bake at 325°F for about 60 minutes, until the edges are set and the center still jiggles slightly.
Turn off the oven and crack the door, letting the cheesecake cool inside for 1 hour. Then chill in the fridge at least 6 hours or overnight.
Top and Serve
Whip the heavy cream with the powdered sugar and cinnamon to soft peaks. Pipe or dollop over the chilled cheesecake before serving.
Notes
Room temp: Cream cheese and eggs must be at room temperature for a lump-free batter.
Crack-free: Mix eggs on low just until combined and cool gradually in the turned-off oven.
Storage: Keeps covered in the fridge up to 5 days, or freeze up to 2 months and thaw overnight.