Crumble cookies into a food processor and pulse until finely ground.
Add brown sugar and ginger and process until the ginger is completely broken down.
With processor running, add melted butter through the feed tube until the crumbs are evenly coated.
Press mixture evenly into the 9-inch springform pan (can also use a 9-inch pie dish), pressing the crumbs about halfway up the sides.
Bake the shell in a preheated 325°F oven until the crust is fragrant and set, about 13-15 minutes. It is a good idea to line the shell with parchment or foil and pie weights or dry beans to ensure the crust will not slump down the sides.
Remove crust from oven and let cool.
For the filling
Sprinkle the gelatin over 2 tablespoons milk to bloom while preparing the pudding.
In a 3-quart saucepan, combine the cream, milk, ¼ cup of the dark brown sugar and salt.
Set over medium-high heat, whisking to ensure the sugar dissolves.
In a separate bowl, whisk the egg yolks, remaining ¼ cup of brown sugar and cornstarch.
When the milk and cream mixture begins to steam slowly, temper the egg yolk mixture by ladling heated milk into yolks, whisking constantly. When the egg yolks are warmed, add to cream and milk mixture and whisk until thickened, about 2-4 minutes.
Remove from heat and strain pudding directly into a food processor.
Add spices, molasses, vanilla, and bloomed gelatin and mix until gelatin dissolves into the pudding.
Add pumpkin and mix until incorporated.
Cool pudding to room temperature then pour into cooled crust and set in the refrigerator to chill completely, about 4-6 hours.
For the meringue (alternatively a 7-minute frosting)
In the bowl of an electric mixer, combine egg whites and sugar.
Set over simmering water and stir constantly until sugar is dissolved and the mixture is at 160°F.
Remove from heat and place on a stand mixer fitted with the whisk attachment. Beat until the mixture is cooled to room temperature.
Beat in the vanilla.
Remove pie from refrigerator and place on serving platter. Top with meringue frosting and brûlée top, if desired.