Preheat the oven to 300°F.
Arrange six 6 oz ramekins in a large, shallow baking pan. Put a large kettle of water on the stove and bring to a boil.
In a 2-quart saucepan, combine the cream, milk, and cinnamon stick and then scrape the seeds from the vanilla bean into the mixture. Warm the cream mixture over medium heat until small bubbles form around the edges, or 170°F. Remove from heat, cover, and steep for 10 minutes. Discard the vanilla bean and cinnamon stick.
While the cream mixture steeps, combine pumpkin puree, maple syrup, cardamom, nutmeg, and salt in a large heavy-bottomed saucepan. Bring to sputtering simmer over medium heat while stirring constantly until thick and shiny, about 10 minutes. Whisk in the warm cream mixture until combined.
In a large bowl, whisk the eggs until pale, about 1 minute. Temper the eggs by slowly adding the warm pumpkin-cream mixture, whisking constantly. Strain the custard through a sieve into a large measuring cup.
Divide the egg mixture among the ramekins. Skim away any foam. Fill the baking pan with hot water until it reaches halfway up the sides of the ramekins. Cover tightly with tinfoil and bake until set and the center still wobbles, about 50 minutes. For a more firm custard, bake for a full 60 minutes.
Remove the ramekins from the water bath and transfer to a wire rack to cool. Cover with plastic wrap and refrigerate until firm.
Just before serving, make the whipped cream. In a cold metal bowl, whip the heavy creme until soft peaks form. Top each pot de crème with a spoonful of cream and a sprinkle of crumbled gingersnap cookies.