Make the gingersnap pecan crust:

Lightly coat the bottom and side of a 9-inch glass pie plate with oil.

In a food processor fitted with the metal chopping blade, combine the gingersnap crumbs, pecans and sugar. Process for 5 to 10 seconds, until the mixture is finely ground. Add the melted butter to the cookie crumb mixture and pulse 3 to 6 times, until the mixture is crumbly.

Scrape the mixture into the oiled pie plate. Using your fingers, press the crumbs firmly and evenly into the bottom and up the sides of the plate. Freeze the pie crust for 15 to 25 minutes, until firm.

Position a rack in the center of the oven and preheat to 350 degrees.

Bake the chilled pie crust for 10 to 15 minutes, until the bottom of the crust bounces back when gently pressed with a finger. Do not over bake. The crust will become firm when cool. Let the crust cool on a wire rack while preparing the  filling. 

Pumpkin mousse filling:

Put the rum and water in a small heat proof cup. Sprinkle the gelatin over the surface of the mixture and let the gelatin soften for 5 minutes.

In a heavy medium saucepan, combine the sugar, cornstarch, cinnamon, ginger and salt. Stir with a small wire whisk until blended. While continuing to stir slowly pour in 1/4 cup of the milk. Add the egg yolks and stir until blended. Stir in the remaining 13/4 cups milk.

Cook the mixture over medium heat, whisking constantly until the mixture starts to bubble. Stop stirring and let the mixture boil for 30 seconds. Remove the pan from the heat. Immediately stir in the softened gelatin until completely dissolved. Stir in the pumpkin.

Press the hot mixture through a fine-meshed sieve into a large non corrosive bowl. Set the bowl with the hot mixture over a larger bowl of ice water. Stir for 3 to 5 minutes, until the mixture is cool and starts to thicken. Remove the bowl from the bowl of ice water. Stir in the vanilla.

In a chilled large bowl, using a hand-held electric mixer or wire whisk, whip the cream until soft mounds barely start to form and the cream is still pourable. Do not over whip the cream.

Using a rubber spatula, fold the whipped cream into the cool pumpkin mixture just until blended. Immediately scrape the mixture into the cooled pie crust. Smooth the top of the mousse with the back of a soup spoon.

Refrigerate the pie for 3 to 4 hours, until set.

Decorate the pie:

In a chilled large bowl, using a hand-held electric mixer or wire whisk, whip the cream with the sugar, rum and vanilla until stiff peaks start to form.

Fill a pastry bag fitted with a closed star tip (such as Ateco #4) with the whipped cream. Pipe lines diagonally across the surface of the pie filling, about an inch apart. Pipe more lines on the diagonal to intersect the first, creating a lattice effect. Pipe a shell border around the edge of the pie. Sprinkle the piped lattice with ginger snap crumbs. Refrigerate until ready to serve.

Yield: 8 servings