1. Cut the whole chicken to pieces
2. Heat the oil in a large pan, add the chicken pieces in batches and brown well.
3. Drain on paper towels.
4. Pour off the excess fat, leaving 1 tbsp in the pan. Return the chicken to the pan with the carrot, celery, onion, peppercorn, garlic, bouquet garni and 1.5 liters of water.
5. Bring the soup to the boil, reduce the heat and simmer for 40 minutes.
6. Strain, returning the stock to the pan.
7. Pull the chicken meat from the bones, shred and set aside.
8. Add the sweet potato to the stock in the pan. Bring to the boil, then reduce the heat and simmer until tender. Add the spinach leaves and cook until wilted. Process in batches in a food processor until finely chopped.
9. Return the spinach to the pan, add the shredded chicken and stir in the cream.
10. Season to taste.
11. Reheat gently before serving but do not allow the soup to boil.