Phở, properly

Where it comes from

Phở is young for a national dish. Most food historians place it in the early twentieth century, in Nam Định province and Hà Nội, where Chinese noodle-soup traditions met a new French appetite for beef. Cattle bones, once discarded, became cheap and plentiful. The usual story is that the name itself comes from the French pot-au-feu, though a Cantonese origin is argued just as firmly. Either way, it began as street food in the north and spread south with the country's upheavals.

The broth is the dish

Everything rests on the broth. Beef bones are blanched, then simmered for hours with onion and ginger that have been charred over a flame until the skins blacken, plus star anise, cinnamon, cloves and coriander seed. The char gives depth and a faint sweetness; the spices give the perfume you smell before the bowl lands. It is skimmed constantly so it stays clear. Ours goes for more than twenty-four hours.

Phở bò is the original: that beef broth over flat rice noodles, with beef sliced rare so it cooks in the bowl, or braised well done. Phở gà swaps in poached chicken and a lighter, cleaner broth. Both are finished with sliced onion and spring onion.

North and south

Northern phở is restrained: clear broth, wider noodles, spring onion, a little chilli and lime, and not much else. Southern phở, shaped in Sài Gòn after 1954, is sweeter and busier: a heap of beansprouts and Thai basil, more cuts of beef, and hoisin and sriracha on the table. Neither is wrong. Our bowls lean northern in the broth and southern in the herb plate, which is the compromise most Vietnamese kitchens abroad settle on.

How to eat it

Taste the broth first, plain, before anything goes in. Then tear the herbs and add them in handfuls, not all at once. Squeeze the lime, add chilli to taste. If you want hoisin, put it in a small dish and dip the meat rather than stirring it through; a whole bowl of dark, sweet broth is the one thing a phở cook will quietly mourn. Chopsticks for noodles, spoon for broth, and it is fine to lift the bowl at the end.

The central cousin

Bún bò Huế comes from the old imperial capital in the middle of the country and is a different animal. The broth is built on beef and pork bones with a great deal of lemongrass, a spoon of fermented shrimp paste for depth, and a slick of chilli oil that turns it orange. The noodles are thick and round rather than flat. It is spicier, funkier and louder than phở, and people who prefer it tend to prefer it fiercely.