Prepare the mushrooms by rinsing away any dirt and removing the tough part at the bottom. Slice the King Oyster mushrooms length ways into thin pieces. Peel away the kaffir lime leaves from the stem. Peel the shallot and cut into quarters. Slice Galangal thinly. Chop off the top and bottom of the lemongrass and place it into a large soup pot, using a pestle to bruise slightly to release the flavour. Add the coconut water, water, shallots, garlic, chillies, kaffir lime leaves and galangal and gently bring to the boil. Allow to simmer for 10-15 minutes. Add the tamarind paste and a good sprinkling of salt and stir. Add the mushrooms and bring back to the boil (don’t overcook as the mushrooms will become chewy) then turn off the heat.
Next add the noodles and tomatoes, and allow to sit for 10-15 minutes. Serve with a sprinkling of fresh chilli, lime wedges and coriander. Enjoy!