Boil about 6 cups water in a medium-large pot, add salt. When the water is boiling add the chicken meat. Cook for 10 to 12 minutes. Turn off heat and close the lid and let the chicken simmer in the hot liquid for about 10 more minutes.Save 2 cups of chicken broth to use later in the soup. You can refrigerate the remaining broth for later use, or use it to cook chicken-broth flavored rice.Remove the chicken and place on a chopping board to cool down. Cut into bite size pieces, set aside. In another pot, heat the oil over medium heat, add the minced shallots, onions, garlic, galangal, lemongrass, kafir leaves, chili, Thai red curry paste, and stir fry.
Add the sliced mushrooms, and stir fry for couple of minutes.
Add the chicken broth, sugar, fish sauce and stir well so nothing sticks to the bottom of the pan. Bring to boil, lower heat and let simmer for around 20-25 minutes. At this point, if you wish, you can strain the aromatics, galagang and lemongrass and discard, if you prefer a clear soup. We like to leave them in the soup for more flavor and texture.
Add the cut chicken pieces and the coconut milk, heat for 3 to 4 minutes, till simmering. Add the lime juice. Stir well and taste, adjust seasoning according to your preference. It should taste tangy, salty, sweet and sour.
Laddle into bowls, sprinkle sliced green onions and/or coriander on top and enjoy hot!