1Bring 4 cups chicken stock, 1/4 cup Thai fish sauce, the juice of 1 lime, 2 crushed wild lime leaves, a 2-inch section of lemongrass, and a 1-inch section of galangal to a boil. Simmer 20 minutes. Strain if desired (though left unstrained in Thailand, the lemongrass, lime leaves, and galangal are not meant to be eaten).
2Add 1/4 pound bite-sized pieces of chicken breast, 1 13.5-ounce can coconut milk, and 2 to 10 (to taste) small red chiles, slightly crushed, and return to a boil. Lower the heat and simmer until the chicken is cooked through, about 2 minutes. Garnish with cilantro leaves and serve.