Preheat oven to 350 degrees F.
In a medium sized glass bowl, add egg yolks and whisk until they are creamy. Add pumpkin, sugar, vanilla, heavy whipping 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 custard.
Pour custard into either 8 custard dishes or an 8 x 8 baking dish. Bake custard until a spoon that is inserted comes out clean (30-35 minutes for baking dish, 20-25 minutes for custard dishes).
12 minutes into the baking process, combine the ginger snaps cookie crumbs and melted butter. Pull the custard from the oven and sprinkle the crumb mixture over the custard. When done, return custard to the oven to finish baking.
When custard is done baking, allow to cool to room temperature.
Just before serving, mix the whipped topping by whisking together the whipping cream, granulated sugar, and pumpkin pie spice until the whipped cream is thickened.
Serve with whole ginger snap cookie on side of custard serving and topped with whipped topping.