You can smell these noodles long before you see the stall where they are cooked, and you can hear the shuffling of the wok as this charred and fragrant dish is fried. Chicken is the most popular meat to use for this dish, and squid is its companion. On the streets it’s cured squid – you’re unlikely to come across it, but fresh makes a sprightly alternative. Tianjin preserved vegetable, called dtang chai in Thai, is usually made from dried cabbage and it can be found in small brown glazed jars in most Asian shops. It can be very salty; if so, give it a quick rinse then leave it to drain and dry. You can use all three of the spring onions and herbs or just one or two, but Siracha sauce is essential – it makes the dish. A relatively mild chilli sauce, this is understandably becoming very popular, and is widely available.
Place the chicken in a bowl, drizzle with a teaspoon of the light soy sauce and leave to marinate for about 5 minutes.
If the rice noodles are not soft and tender, tease them apart and steam them for a minute or so, then allow to cool before separating the noodles once more.
Heat the wok over a high heat, then add the oil. Add the chicken and squid and stir-fry until coloured and almost cooked. Turn down the heat to low and add the preserved vegetable, garlic paste, and about half of each of the spring onions, coriander and Asian celery. Add the noodles and leave for a few moments to sear and colour. Turn up the heat slightly and drizzle in the soy sauce, then season with the sugar and a good pinch of pepper. Cook for about 2 minutes to caramelise the noodles, stirring occasionally and carefully to avoid breaking up the noodles too much. Add a little extra oil, if necessary, but not too much – otherwise the noodles will clump together. Shift the noodles to one side of the wok and add a little extra oil. Turn up the heat, then crack in the egg and fry, trying to keep the yolk intact until just set. Fold the egg back into the noodles, along with most of the rest of the spring onions, coriander and Asian celery, another pinch of pepper and the Chinese lettuce.
Sprinkle with the remainder of the Asian celery, spring onions, coriander and white pepper. Serve with a bowl of Siracha sauce.