Combine the graham cracker crumbs, granulated sugar, cinnamon, and melted butter in a medium bowl until evenly moistened. Firmly press the mixture into the bottom and slightly up the sides of a 9-inch springform pan. Refrigerate while preparing the filling.
Beat the softened cream cheese until smooth and creamy. Add the pumpkin puree, powdered sugar, vanilla extract, pumpkin pie spice, and cinnamon, then continue mixing until the filling is completely smooth and well combined.
In a separate bowl, whip the cold heavy cream until stiff peaks form. Gently fold the whipped cream into the pumpkin mixture using a rubber spatula until no streaks remain. Spread the filling evenly over the prepared crust and smooth the top with an offset spatula.
Cover the cheesecake and refrigerate for at least 6 hours or overnight until fully set. Remove from the springform pan, garnish with whipped cream, a light sprinkle of cinnamon, and crushed graham crackers if desired before slicing and serving.
