Bangkok’s best street food has always existed on a kind of mental map for Thai food writer Choltanutkun Tun-atiruj. It is built from habit, cravings and neighbourhood rhythms: the office crowds, the schools, the university nearby and the vendors selling everything from moo ping (grilled pork skewers) and sticky rice to pad thai and kuay teow reua – a bowl of rice noodles in dark broth flavoured with cow or pig’s blood, then topped with meat and spices.