Pak Boong Tom Yum

Pak boong tom yum is a Central Thai household soup, not a restaurant tom yum. Where the famous tom yum kung uses shrimp and chile paste, this version is a vegetable-only weeknight read of the same template — the same lemongrass-galangal-lime aromatic backbone, but with morning glory as the body. The dish belongs to the Thai family of khaeng som and tom yum-style clear soups that cooks make from whatever vegetable came home from market that day.

Central Thai weeknight soup, not the restaurant tom yum kung. Same lemongrass-galangal-kaffir backbone, water spinach as the body, no chile paste, no coconut. Lime juice goes in off the heat — limonin turns bitter above 70°C.

Clear broth with green confetti — water spinach stems hollow and crunchy like nature's straws, leaves silky. The aromatics hit first (lemongrass, galangal, kaffir), then the lime sour, then a chile heat that walks up the back of the throat slowly. No coconut, no chile paste, no cream — every flavour is broth-and-aromatic transparent. If the spinach is dark olive instead of bright green, it overcooked; if the lime tastes acrid, it was added in the boil.

Two rules separate this from a generic green-vegetable soup. One: lime juice goes in OFF the heat — limonin in lime peel becomes bitter above 70°C, and the sour-aroma volatiles flash off in a boil. Two: water spinach has hollow stems that fill with broth on first contact and lose crunch within 2 minutes — so the cook plans to eat it within 5 minutes of plating, not later. This is not a soup that holds.