Simmer the star anise in the chicken broth for 10 minutes. Remove the anise and add the gelatin and fresh pepper to the warm broth. Add salt if needed. Pour the gelee into a shallow dish and let it chill until firm in the refrigerator.
Divide the foie gras into 4 equal pieces, and using your hands, roll each into a round ball Then roll each ball in the chopped truffles until evenly coated. Chill until firm.
To serve: Chop the firm gelatin into small cubes and divide onto 4 plates. Place a 'truffle' in the center of each plate, and garnish with dried celery leaves. Serve with toasted sourdough bread.
Recipe courtesy of Gerard Vie, Les Trois Marches, Versailles, France