Place the potato in saucepan, cover with cold water and bring to a boil. When soft, drain and chop coarsely, set aside. Heat the butter in a saucepan, add the chervil, cover and cook over very low heat for 5 minutes. Stir in the chicken stock and simmer for 10 minutes. Pour into a food processor, add the potato and blend until smooth. Return to the saucepan and stir in the cream, wild rice and cooked chicken. Season to taste and heat thoroughly. Garnish and serve.
Makes approximately 6 servings.