Soften the gelatin in 1/2 cup of cold water. Place over low heat and bring almost to a boil, stirring to dissolve. Beat the egg yolks and sugar until very light. Stir the gelatin into the egg mixture. Cool. Gradually add the rum, beating constantly. Whip the cream until it stands in soft peaks and fold it into gelatin mixture. Cool until the mixture begins to set, then spoon it into the crumb crust and chill until firm enough to cut. Grate the unsweetened chocolate over the top before serving.
Combine the ingredients and press into a 9-inch pie pan.