Combine first 4 ingredients. Press mixture on bottom of a 9 inch pie pan . Refrigerate.
Melt chocolate over a double boiler. Dissolve gelatin in cold water. If using gelatin sheets, immerse in cold water.
Cream sugar and egg yolks. Slowly pour the boiling milk over egg mixture. Pour into saucepan.
Stir with a wooden spoon over low heat until the mixture coats the back of the spoon.
Do not boil. Stir in the gelatin and melted chocolate. Strain into a bowl. Cool mixture.
Whip the heavy cream to a medium peak. Fold 2/3 into the cool chocolate custard. Save remaining for garnish.
Pour into prepared pie. Refrigerate for 2 hours.
Decorate with whipped cream and chocolate shavings.