Stir the graham cracker crumbs, granulated sugar, and cinnamon together in a bowl. Pour in the melted butter and mix until it looks like wet sand.
Press the mixture firmly into the bottom and slightly up the sides of a 9-inch springform pan, packing it down tight with the flat bottom of a measuring cup. Place in the freezer while you make the filling.
Make the Filling
Spread the pumpkin puree on paper towels and press out as much liquid as possible, changing the towels a few times. This step is essential for a firm set.
In a separate bowl, beat the heavy cream to stiff peaks and set aside.
Beat the softened cream cheese with the powdered sugar, brown sugar, pumpkin pie spice, cinnamon, and vanilla until completely smooth, scraping the bowl so there are no lumps.
Mix in the blotted pumpkin until the color is even. Gently fold in the whipped cream with a spatula until no white streaks remain, being careful not to deflate it.
Chill and Set
Spread the filling over the chilled crust and smooth the top. Cover and refrigerate at least 6 hours, or overnight, until firm and sliceable.
Serve topped with extra whipped cream and a dusting of cinnamon. Slice with a thin, sharp knife, wiping it clean between cuts.
Notes
Blot the pumpkin: Canned pumpkin holds a lot of water. Blot it three or four times so the filling sets firm instead of runny.
Cream cheese matters: Use full-fat brick-style cream cheese, softened to room temperature. Spreadable or low-fat cream cheese will not set.
Gingersnap swap: Trade the graham crumbs for gingersnap crumbs for a spicier crust.
Storage: Keeps covered in the fridge 4 to 5 days, or wrapped in the freezer up to a month. Thaw overnight in the fridge.