Shrimp and Mushroom Soup

Heat the chicken stock in a saucepan. Add the mushroom strips and simmer for about 10 minutes over low heat. In a mortar, pound together the peppercorns, coriander roots and garlic to a paste. Heat the vegetable oil in a small frying pan and fry the paste until it is light brown. Transfer the paste to the stock. Bring the combination to a boil and cook for 1 minute. Add the shrimp to the liquid