25 gingersnap cookies, broken into pieces (about 2 1/4 c.)
1 tbsp. sugar
5 tbsp. unsalted butter, melted
2 tbsp. plus 1 1/2 c. chilled heavy whipping cream
2 1/4 tsp. unflavored gelatin (from 2 envelopes)
3 large egg yolks
1/2 c. brown sugar
1 tsp. cinnamon
1/4 tsp. ground ginger
1/4 tsp. ground allspice
1/8 tsp. salt
1 1/4 c. canned pumpkin
1/4 c. sugar
For crust: Preheat oven to 350º. Butter 9 in. glass pie dish. Grind gingersnap cookies with sugar in processor until coarse crumbs form; transfer crumbs to bowl and mix in melted butter. Press crumb mixture over bottom and up sides of prepared dish. Bake crust until puffed, about 6 min. Transfer to rack. Using back of spoon, lightly press sides and bottom crust to original shape; cool.
Place 2 tbsp. cream in small cup. Sprinkle gelatin over. Let stand until gelatin softens and all of cream is absorbed, about 20 min. Combine 1/2 c. cream, egg yolks, brown sugar, spices and 1/8 tsp. salt in heavy medium saucepan. Whisk until well blended. Whisk in softened gelatin mixture. Whisk over medium low heat until gelatin dissolves and custard thickens enough to coat spoon, about 7 min. (do not boil). Immediately transfer custard to bowl; whisk in pumpkin and 1/4 c. sugar. Place bowl with custard over bowl of ice and water. Let cool until mixture is cold and beginning to set; stirring occasionally, about 25 min.
Beat remaining 1 cup cream in medium bowl until peaks form. Fold half of cream into pumpkin mixture. Transfer filling to prepared crust. Spoon remaining whipped cream into pastry bag fitted with small star tip. Pipe cream in rosettes around edge of pie. Chill until filling sets, at least 3 hours and up to 1 day.