In a medium-sized pot over medium heat, bring chicken broth, salt, galangal, lemongrass, shallot, garlic, chilies and mushrooms to a boil and let roll for 5 minutes.
Add coconut milk and fish sauce, bring back to a boil and let roll for about 3-5 minutes.
Add fish sauce, chicken and tomatoes and let the chicken cook for about 5-7 minutes.
Add lime juice and sugar, stir to mix well. Continue to cook for 1 more minute. Turn off the heat.
Add green onion, sawtooth coriander and cilantro. Tear Magrud lime leaves along the rib, discard the rib and add all the leaves to the soup. Use a ladle, stir to mix well.
Serve with steamed jasmine rice or brown rice. The galangal, lemongrass and Magrud lime leaves can be eaten but they are fibrous, spicy and slightly bitter. Chef Nuit likes to chew and discard the fibre, otherwise you can remove before serving.