> bring coconut milk and broth to a boil, add thinly sliced galangal, minced ginger, and thai chiles to soup and simmer on medium for 10 minutes.
Add chicken slices and stir occasionally until chicken is tenderly cooked.
Add straw mushrooms (drained), and thinly sliced, deveined lime leaves (optional: cut a few cross-sections of lemon grass and add to the soup) (optional : cut tomatoes into largish cubes about 1" square, and add to soup).
Add more thai chiles if it is not spicy enough for you -- simmer for 10 more minutes.
When you are ready to serve, turn off the heat, add brown sugar, lime juice, fish sauce, and stir well.