Tom Yum Fish with Roasted Chilies and Thai Herbs Soup is the best Thai soup of all. Here in this less typical version of the dish, fresh fish is simmered in a stock flavored with lemongrass, kaffir lime leaves, sea salt, tamarind and roasted red chilies. Note it is best to serve any type of Tom Yum soup hot, to enjoy its fresh herbal and citrus flavors at their peak.