Amok Trey.

Amok is not one dish but a technique found across mainland Southeast Asia — the Lao mok, the Thai hor mok, the Malay otak-otak all steam seasoned fish inside a leaf — and Cambodians, Thais and Lao each claim their version as the original. The honest answer is that the method almost certainly predates the modern borders entirely. What is specific to Cambodia is the seasoning and the set: Khmer amok is built on yellow kroeung with almost no chile, uses freshwater fish from the Tonlé Sap rather than sea fish, and is enriched with egg so it firms into a custard rather than staying a loose paste.

The fish matters more than any restaurant will tell you. Traditionally amok is made with snakehead fish or featherback from the great lake, whose flesh is firm and slightly gelatinous and holds together through steaming. Cambodians also line the banana leaf cup with slok ngor — the leaves of Morinda citrifolia, faintly bitter and slightly medicinal — which balances all that coconut fat. Neither is easy to find abroad, and this is the point where honesty beats pretence: with a firm white sea fish and a few spinach or young chard leaves, you get a genuinely good amok that a Khmer cook would still recognise, minus one layer of bitterness.

In Cambodia amok belongs to celebrations and to the Water Festival, and it is the dish put in front of every visitor to Siem Reap. That popularity has flattened it — tourist versions are often coconut soup poured into a leaf, thickened with cornflour, barely steamed. The real thing is denser than you expect, sets enough to hold a spoon mark, and is made in small portions because it is rich. Building it at home in ramekins or small heatproof bowls, with a banana leaf lining if you can get one, gets you far closer than most restaurants outside the country manage.