1. Make the crust: Preheat oven to 350 degrees. Process gingersnaps, granulated sugar, and salt in a food processor until finely ground. Add butter, and process until combined. Divide mixture among six 5-inch pie plates, pressing into bottom and up sides. Place on a baking sheet, and bake until darkened and firm, 11 to 13 minutes. Let cool 5 minutes. Using an offset spatula, carefully unmold crusts, and return to sheet to cool. (Crusts can be stored in pie plates in airtight containers for up to 2 days.)

2. Make the filling: Sprinkle gelatin over cold water in a bowl. Let stand until softened, about 5 minutes.

3. Combine pumpkin, egg yolks, 1/4 cup granulated sugar, milk, salt, and spices in a saucepan over medium heat. Cook, stirring, until mixture begins to thicken, about 8 minutes. Do not boil. Remove from heat. Stir in gelatin mixture until dissolved. Let cool completely.

4. Beat egg whites with a mixer until soft peaks form. Gradually add remaining 1/2 cup granulated sugar, beating until stiff peaks form. Whisk one-third of beaten egg whites into cooled pumpkin mixture. Gently fold in remaining whites. (Filling can be refrigerated, covered, overnight.) Spoon into pie shells, and refrigerate for at least 1 hour (or up to 2 hours).

5. Make the garnish: Using a vegetable peeler, shave pumpkin into thin, wide ribbons. Bring water, brown sugar, cinnamon sticks, and ginger to a boil in a saucepan over medium heat. Cook until reduced by half, about 5 minutes. Add pumpkin pieces, and reduce heat. Simmer gently until tender and translucent, about 8 minutes. Pour into a bowl, and let cool completely. (Garnish can stand at room temperature for up to 3 hours.) Top each pie with 3 or 4 pumpkin pieces, discarding syrup. Serve immediately.

6. Variation: This recipe also can make two 8-inch pies; be sure to leave the crust in the pie plate before adding the filling.