Begin by crumbling cookies in a food processor. Then combine with melted butter. Press the mixture into the bottom of a 9-inch springform pan. Place the pan on a cookie sheet to catch drips and bake for 10-12 minute Remove from the oven and cool on a wire rack.
Beat the cream cheese in an electric mixer on low until the cream cheese is very smooth.
Gradually add the sugars.
Add the eggs, one at a time.
Add the pumpkin puree and mix until just combined. Make sure to scape down the mixing bowl a couple of time during the process to ensure there are no lumps stuck to the bowl and the batter is very smooth.
Stir in heavy cream, cinnamon, and allspice.
Pour the batter into the prepared pan and set the pan back on the baking sheet. Bake until the edges are set and the center moves only slightly when the pan is shaken. Baking time may vary a little, start checking it after 1 hour. When it's done baking, turn off the oven and prop the door open with a wooden spoon and allow the cake to cool there for another hour.
Chill for at least 12 hours, can be made up to 2 days in advance.
Make the topping by whipping the heavy cream, sugar, and vanilla until you have stiff peaks. Apply topping shortly before serving and enjoy!