Laos: the river itself, dried and fried
Kaipen is freshwater weed lifted from the Mekong, washed, pressed flat with sesame and garlic, dried in the sun and fried to a crisp. It is eaten with jeow bong, a chilli paste with dried buffalo skin in it, and it tastes precisely of the river it came from.
It is also seasonal in a way most menu items are not. The weed is gathered when the water is low and clear, which is why the good version appears in the cool months and the rest of the year offers something thicker and less interesting.
Thailand: noodles measured by the boat
Ayutthaya's boat noodles were sold from the canals, in bowls small enough to pass between a moving boat and the bank without spilling. The size stayed after the boats mostly went: a portion is still a few mouthfuls, and a proper sitting is four or five bowls stacked beside you.
The broth is dark with blood and spice, and the counting of empty bowls is part of the meal rather than a gimmick. The stalls on the island keep it; the ones on the highway rarely do.
Vietnam and Cambodia: court and country
Hue cooked for an emperor and never stopped. Its dishes are small, numerous and exact: banh khoai, com hen built on clams no bigger than a fingernail, a table of ten things rather than one large plate. The restraint is imperial, not modest.
Cambodia goes the other way. Prahok, fermented fish paste, is the base note under a great deal of Khmer cooking, and the fermentation season follows the fish run off the Tonlé Sap. Learning to like it is the shortest route into the food of the lower river.
