Set aside 1/4 cup of the toasted hazelnuts for the chopped outside layer and a few whole ones for the inside of the truffles.
Put all remaining ingredients in a high speed blender to create a paste.
Start assembling the truffles by making small balls with your hands and inserting a whole hazelnut in the middle. Roll them in chopped hazelnuts. Refrigerate for about 1 hour and serve.