Preheat oven to 275 degrees F.
In a food processor, whirl chocolate wafers to fine crumbs. Add butter, whirl another 5 to 10 seconds.
Press crumb mixture firmly and evenly into a 10-inch pie plate. Bake crust approximately 5 minutes to set it. Remove from oven and cool on a wire rack.
In a small bowl, soften gelatin with 1/4 cup cold milk; set aside.
In a double boiler over hot water, place egg yolks; beat slightly. Add sugar and remaining milk; stir constantly and cook for 10 minutes or until the internal temperature registers at least 160 degrees F. on your cooking thermometer and the mixture coats a spoon.
Remove from heat. Stir in prepared gelatin mixture, salt, and nutmeg; stir until gelatin is dissolved. Very slowly add cream sherry, stirring constantly. Remove from heat. Place the custard mixture into the refrigerator to thicken. When thickened, remove from refrigerator and proceed with recipe.
In a medium bowl, beat whipping cream until thickened; set aside. In a large bowl, beat egg whites until stiff peaks form. Gently fold whipped cream into egg whites; gently fold this mixture into thickened custard mixture.
Pour custard mixture into baked pie shell. Place into the refrigerator for at least 8 hours or overnight before serving.
Makes 8 servings.