Chill a bowl and a rotary beater in the refrigerator. Chop almonds coarsely and set aside. Pour water in a cup and sprinkle gelatin over water. Let stand about 5 minutes to soften.
Beat slightly egg yolks and set aside. Mix milk, sugar, salt thoroughly in a top of a double boiler and heat until milk is scalded. Vigorously stir about 3 tablespoons of hot mixture into beaten egg yolks. Immediately blend into mixture in the double-boiler top. Stirring constantly, cook over simmering water until mixture coats a silver spoon. Immediately remove from heat.
Blend in softened gelatin, stirring until gelatin is completely dissolved. Cool; chill until mixture begins to gel.
Using the chilled bowl and beater, beat whipping cream until it piles softly. Set in refrigerator.
Using a clean beater, beat 3 egg whites until frothy. Add sugar gradually beating well after each addition. Beat until rounded peaks are formed. Fold beaten egg whites and whipped cream into custard mixture with sherry and almond extract. Fold in the chopped toasted almonds. Turn into cooled pie shell. Chill in refrigerator 2 or 3 hours, or until firm. Garnish with chocolate curls made by pulling a chocolate bar across shredder.