For the Crust:

1. Add the graham crackers and brown sugar to the bowl of a food processor and process for about 20 seconds, until finely ground and well combined. Add butter and pulse 6 to 8 times, until mixture resembles wet sand.
2. Dump the graham cracker mixture into a greased 9-inch pie plate. Press the pretzel mixture evenly into the bottom and up the sides of the plate. Transfer to the freezer and freeze for at least an hour and up to overnight before filling. (Alternatively, you can bake the crust at 350 degrees F for 8-10 minutes, then cool completely before filling.)

For the Pie:

1. Stir together cinnamon, cardamom, ginger, allspice, and nutmeg in a small bowl and set aside.
2. Add the cream cheese, pumpkin, 1/2 cup maple syrup, vanilla, salt, and 1 tablespoon cinnamon spice mixture in the bowl of a stand mixer fitted with the whisk attachment. Beat on medium-high speed for about 2 minutes, stopping to scrape down the sides as necessary, until light and fluffy.
3. Sprinkle gelatin over 1/4 cup water in a small microwave-safe bowl. Allow the gelatin to “bloom” for 1-2 minutes. Microwave the gelatin mixture for about 30 seconds to dissolve the gelatin. Turn the stand mixer to medium and immediately drizzle in the dissolved gelatin (allowing it to sit too long will cause it to harden). Next, gradually pour in 1/2 cup heavy cream and continue to beat for about 20 seconds, until well combined and fluffy. Transfer mixture to a large bowl.
4. Wipe the mixer bowl clean (no need to fully wash). Add the remaining cinnamon spice mixture, remaining 2 tablespoons maple syrup, and remaining 2 cups heavy cream in a bowl of stand mixer. Beat, starting on low and increasing to medium-high speed, for 1 to 2 minutes, until stiff peaks form.
5. Fold about 1 cup whipped cream into the pumpkin mixture using a large spatula. Transfer the pumpkin mixture to the prepared pie crust, and spread in an even layer with an offset spatula. Top with remaining whipped cream.
6. Chill the pie, uncovered, until filling is cold and set, at least 4 hours and up to 24 hours. Garnish with a dusting of ground cinnamon and cinnamon sticks. Serve cold. This pie keeps well in the fridge for up to 3 days.