An Ancient Siamese Recipe for Tom Kha Pet (1890 AD) Duck Simmered in Light Coconut Cream and Young Galangal, and Served with Sour-Sweet Roasted Chili Jam
(Tom Kha Bpet; ต้มข่าเป็ด จิ้มน้ำพริกเผาแบบโบราณ)
Tom kha is a well-known and much-loved Thai soup: a creamy, soothing coconut blend, a warm, silky broth in which chicken, mainly, is simmered with young galangal, mushrooms, and, at times, charred-grilled banana blossoms. In other versions, lemongrass and kaffir lime leaves are added, blurring the boundaries between tom kha and the coconut-based tom yam soup (tom yum kati; ต้มยำกะทิ).
However, in the late 19th century, tom kha was not a soup at all: it was a dish of chicken or duck simmered in a light coconut broth with a generous amount of galangal. The coconut broth added sweetness to the meat, and the galangal helped to mellow the meat odor. It was then served with a basic roasted chili jam as a dipping relish seasoned along the salty-sour-sweet spectrum.