Nonstick cooking spray
1/4 cup fine gingersnap crumbs (about 6 gingersnaps)
1/2 cup sugar
1 cup evaporated skim milk
1 envelope unflavored gelatin
1 1/4 teaspoons ground ginger
1 large egg yolk
1 can (1 pound) solid-pack pumpkin
3 large egg whites
1/4 teaspoon cream of tartar
Lightly coat the bottom and sides of a 9-inch pie pan with the cooking spray.
Place the gingersnap crumbs into the coated pie pan.
Tilt the pan from side to side until the sides and bottom are lightly but evenly dusted with the crumbs.
Refrigerate while you prepare the filling.
In a small saucepan, combine 1/4 cup of the sugar and 1/4 cup of the milk; sprinkle the gelatin and ginger evenly over the surface and let soften for 5 minutes.
Set the saucepan over moderately low heat and cook, stirring, for 5 to 6 minutes or until the gelatin and sugar dissolve.
Remove from the heat.
In a small bowl, beat the egg yolk and remaining milk together, then slowly whisk in the hot gelatin mixture.
Transfer the mixture back to the saucepan, set over low heat, and cook, stirring, for 2 to 3 minutes or until slightly thickened; be careful not to boil or the mixture will curdle.
Transfer the filling to a large bowl, blend in the pumpkin, cover and refrigerate for 20 to 30 minutes, stirring occasionally, until the mixture mounds slightly when dropped from a spoon.
In the large bowl of an electric mixer, beat the egg whites and cream of tartar at moderate speed until foamy; slowly add the remaining 1/4 cup sugar and beat at moderately high speed until the whites hold soft peaks.
With a rubber spatula, fold the egg whites into the pumpkin mixture and spoon into the crust.
Refrigerate at least 8 hours before serving.