Make the crust: Preheat the oven to 325 degrees F. Pulse the cookies, crystallized ginger and brown sugar in a food processor until finely ground. Add the melted butter and pulse to combine. Press the mixture into the bottom and up the side of a 9-inch pie plate. Bake until set and slightly dry around the edge, 10 to 12 minutes. Transfer to a rack and let cool.
Make the filling: Whisk the pumpkin puree, coconut milk, granulated sugar, eggs, vanilla, ground ginger and salt in a medium bowl until smooth. Pour into the cooled crust. Bake until the filling is set and no longer looks wet, 1 hour 15 minutes. Transfer to the rack and let cool completely, at least 2 hours.
Make the topping: Beat the heavy cream, brown sugar and pie spice in a bowl with a mixer on medium-high speed until stiff peaks form, 3 minutes. Spread on the pie; sprinkle with more pie spice.
Photograph by Ryan Liebe