Bring chicken or game stock to simmer in a heavy bottom saucepan. Add lemon peel, rosemary and drain artichokes. Then simmer for 15 minutes without boiling,covering with lid. Remove lemon and rosemary. Then add pre cooked lentils, hazelnuts and celery. Return to heat and simmer for further 10 minutes or so more till artichokes are tender. Finish with 50gram butter gently shaken into casserole. Source: My collection - Jeff Baker - J Bakers Bistro Moderne