Make a paste for the soup by adding coriander, peppercorns, shallots, ginger and salt together. Heat oil in a pan and fry the paste with minced Garlic. Add 4-5 cups potable water. Seaon with palm sugar, tamarind puree and fish sauce. Add mushrooms and fish. Bring to boil.
Add cut Spring Onion, Ginger, and chillis. Before serving add lime juice and coriander leaves.