In a mortar and pestle or a food processor, pound the hazelnuts until finely ground.

In a medium heavy saucepan, bring the cream to a boil over medium high heat (watch carefully that it does not boil over). Add the sugar and stir until it has dissolved. Stir in the hazelnuts, bring back up to the boil and remove from the heat. Cool the mixture almost to room temperature. Preheat the oven to 350 degrees. In a large mixing bowl, beat the egg and the egg yolks together until evenly blended. Slowly pour the cream mixture in, stirring all the time, until absorbed. Add the Frangelico and then strain the mixture through a fine sieve into a large measuring cup with a lip, pressing hard against the mesh to extract all the flavor from the nuts. Pour the custard mixture into twelve 2 ounce ramekins and arrange them in a large roasting pan. Pour a little boiling water in the base of the pan, to come about halfway up the sides of the little custard pots. Bake on the middle rack until the custards are set in the center, about 35 minutes. Remove from the pan and cool to room temperature, then chill for at least 1 hour. Serve 2 or 3 little custards per person and, using a vegetable peeler, shave a few small curls of chocolate over the top of each.