Preheat oven to 350 degrees.
Crack open 8 eggs, and separate the whites from the yolks. In a medium-sized glass bowl add egg yolks and whisk until they are creamy. Add pumpkin,1/2 cup sugar, vanilla, 1 3/4 cups of heavy cream, and pumpkin pie spice and combine until all are incorporated.
Cook custard mixture in a double boiler, and stir until custard has thickened, and a spoon remains coated when inserted into the custard. Pour custard into either 8 custard dishes, or an 8 x 8 baking dish. Bake custard for about 30-35 minutes or until a spoon is inserted comes out clean.
Halfway through the baking process combine the 1 cup gingersnaps and 1 tablespoon melted butter, and sprinkle the crumb mixture over the custard while it is baking by removing the dishes from the oven, adding gingersnap crumb mixture and returning the dishes to the oven to finish baking. If you are using small individual custard dishes check the custard at 20-25 minutes. Allow the custard to cool to room temperature.
Just before serving mix the pumpkin pie spice-infused whipped cream by whisking together the 1 cup whipping cream, 1 tablespoon granulated sugar, and 1/4 teaspoon pumpkin pie spice until the whipped cream is thickened.