Wattana Panich is certainly a contender for the world's oldest continually cooked dish. Since they opened more than four decades ago, the same beef broth has simmered in a cauldron at the front of the shop.
There's no recipe here, the cooks simple add more ingredients - black peppercorns, coriander root, garlic, star anise, fistfuls of secret Chinese herbs along with fresh cuts of beef that are simmered slowly for at least eight hours until tender, the fat slowly melting and emulsifying in the stew. The taste and smell along with years of dedication to the same dish are what's needed for absolute consistency.
Each night, what's left of the day's soup is continually reduced and then used as the stock base for the following day.
The old shophouse eatery sits among the towering glassy buildings in the ever modernising and high end Ekkamai neighbourhood resisting efforts to change themselves. This is a city known for its competitive food scene and Wattana Panich has lasted the test of time passing down through three generations of the same family.
Like many successful shophouse restaurants in Bangkok, it started as a humble pushcart. The current owner's grandfather cooked the beef stew from a stall along the Chao Phraya river building a loyal enough customer base to open a permanent bricks-and-mortar shop.
The interior is as old as the shophouse - a cluttered mess of metal-clad tables, piles of pots and pans, stacks of beer and white tiled walls hidden behind Thai calendars, framed photos of the royal family, antiques and small Thai shrines. Toward the street side open-fronted entrance, the kitchen area holds the simmering pan of glistening beef and stock below shelves of towering melamine plastic bowls and whirling ceiling fans.
It's a tad more than similar dishes elsewhere, but the 80-100 THB (US $2.50 - $3.20) could never be classed as expensive and the quality of the ingredients make it worth the extra spend.