Until recently, the bun cha I had eaten in the United States, France, Hong Kong and Australia, had involved a huge bowl of rice vermicelli on top of shredded lettuce with a few fresh herbs, some grilled pork and a small bowl of nuoc cham - fish sauce mixed with lime juice, rice vinegar and shredded vegetables - that you pour over the noodles.

On a recent trip to Ho Chi Minh, Vietnam, however, it was served in such a different way that I asked my friend - who has lived in Hanoi for several years - if it was the correct order. She assured me it was.

A small portion of rice noodles came on one plate, a huge pile of fresh herbs on another, with charcoal-grilled pork meatballs and sliced pork served in a bowl of nuoc cham. The ingredients were about the same - and both versions delicious - but the proportions were very different. The one served in Vietnam is DIY; you mix the ingredients in the proportions you want, and it tastes lighter and fresher due to there being more herbs. It's also more of a snack: it would take at least two orders of the Ho Chi Minh bun cha to make up one portion of the dish served at a Vietnamese restaurant in Hong Kong.

Bun cha is a street-food speciality of Hanoi and, given how delicious it is in Ho Chi Minh, the version served in the capital must be truly amazing.