Prepare the ingredients: peel the shallots or onion and chop roughly. Wash the galangal and turmeric and slice them (¼" or 1 cm). Wash the mushrooms and dry, chop the stems off. Soak the basil, cilantro, scallion and kaffir lime leaves in cold water for a few minutes and drain. Put aside a few leaves of cilantro and basil for garnish.
Put the coconut oil in a medium soup pot over medium heat. Add the shallots or onion and sauté for a couple of minutes. Add the mushrooms and continue to sauté for 1 - 2 minutes. Add the vegetable broth, water, galangal, turmeric and herbs to the pot and raise the heat to high, and bring to a boil.
Boil for 5 minutes, then lower to a simmer. Add the fish sauce and coconut milk, and cook for another 5 - 10 minutes.
Meanwhile, prepare the rice noodles. Fill a large saucepan with water and bring into a boil. Stir in the noodles and cook them until they are al dente, about five minutes. Drain and rinse them under cold water.
Put a handful of noodles into bowls, ladle the soup over, and garnish with chili flakes, basil or cilantro, and serve with wedges of lime on the side.