Oyster omelette, or o-a-chian, is a classic Taiwanese dish that is commonly found in night markets in Taipei. It is made by frying a mixture of eggs, oysters, and vegetables, such as sweet potato starch, cabbage, and bean sprouts. The omelette is then topped with a tangy and savory sauce. The combination of the crispy edges, tender oysters, and flavorful sauce creates a delicious and satisfying dish.