Ingredients:
1 liter water
1 chicken breast
1 onion, chopped
4 lime leaves
3 stems lemon grass, crushed
3 cm piece ginger, sliced
1 small red chili, deseeded and sliced
100 grams oyster or shiitake mushrooms, sliced
2 water chestnuts, sliced
1 teaspoon Thai fish sauce
juice of 1 lime and 1/2 lemon
200 ml coconut milk
freshly ground black pepper
salt
2 teaspoon coriander, chopped

Directions:
In a large saucepan, heat the water with the chicken, onion, lime leaves, lemon grass and chili. Bring to a boil, cover tightly, reduce the heat and simmer for 20 minutes, until the chicken is tender. Remove chicken and simmer for another 15 minutes.
Strain the broth. Discard the spices, except for a few sliced of chili, which add color to the soup. Return the broth to the pan. Add the chicken meat, mushrooms and water chestnuts.
Simmer for 3 minutes and then add the fish sauce, lime and lemon juice and coconut milk. Remove from the heat and season to taste.
Add some chopped coriander to each soup bowl. Reheat the soup but do not boil. Pour over and serve.