One of the best-known dishes, not just in Koh Samui but throughout Thailand, tom yum is a delectable shrimp/prawn soup. The spicy, sour, and delightfully aromatic dish is usually served as an appetiser to rice. Tom yum, in its basic form, is a tantalising combination of shallots, lemongrass, fish sauce, ginger, shrimps, mushrooms, kaffir lime leaves, lime juice, and chilli peppers. Thanks to the dish's wide popularity, a few regional varieties of the dish have emerged over the years, such as tom yum gai and tom yum talay, with added chicken and mixed seafood, respectively.