Heat a large soup pot, add the oil. Add the onions, lemongrass, and all the peppers and chiles and saute until soft, stirring frequently. Add the ginger, garlic and mushrooms, reduce the heat and continue to saute for 10 minutes. Turn the heat to very low and stir in the coconut milk, stock and chicken. Heat very slowly, but do not allow the soup to boil! Simmer until the chicken is just tender. Add the remaining ingredients, garnish with a couple of Thai Chiles, if desired, and serve. Heat Scale: Very Hot