1) In a blender or in a Mouli grater, grind hazelnuts.
2) Line bottom of a 9-by-5-by-3-inch loaf pan with waxed paper.
3) In small, heavy saucepan, combine chocolate and cream.
4) Over low heat, place the saucepan and heat the mixture just until chocolate is melted.
5) Remove from heat.
6) In medium bowl, combine nuts, sugar, and egg white.
7) Using a wooden spoon, stir until combined.
8) Stir in chocolate mixture and liqueur, to combine well.
9) Transfer the mixture into prepared pan, or use to fill fluted paper bonbon cups.
10) Refrigerate until firm.
11) Cut into 3/4-inch squares.
12) Cover with foil, store in refrigerator until consumed.
13) Serve the hazlenut truffles as sweet snack or crush them on top of puddings and ice cream.