Xi'an Biang Biang Noodles with Chilli Oil

Tip 500 g Plain flour into a big bowl with 8 g Salt. Pour in 260 ml Water in a slow stream, stirring with chopsticks or a fork until ragged shaggy clumps form and no dry flour is left. Knead on a lightly oiled bench for 5 min, until the dough turns from shaggy to smooth, tacky but not sticky. It should spring back when you poke it.

⚠ Tip: It will look too wet and sticky — that is right. Resist adding flour; a soft dough is what stretches without snapping.

Shape into a ball, wipe with 1 tbsp Neutral oil so it does not dry out, cover and leave for 40 min. The gluten needs the rest — un-rested dough tears when you slap it.

Cut the dough into 500 g equal pieces, roll each into a thumb-thick baton about a hand long, rub every baton with oil and lay them on a tray. Cover again and rest for another 20 min.

Toast 1 tsp Sichuan peppercorns in a dry wok over medium heat for 40 sec, until they crackle and smell tingly. Grind to a powder and leave aside. In a wide heatproof bowl (the one you will tip the oil into), combine 6 tbsp Sichuan chilli flakes and 1 tsp Cayenne pepper with 2 tbsp Light soy sauce, 3 tbsp Chinkiang vinegar, half the Sichuan peppercorns and 1 tbsp Toasted sesame seeds. Mince the Garlic and Ginger and finely slice the Spring onions, keeping them all within reach.

⚠ Tip: Keep chilli, garlic and ginger separate from the wet mixture — they go on last so the oil hits them fresh.

Bring a large pot of 3 l Water to a hard boil and salt it. Keep it at a rolling boil — noodles dropped into lazy water turn gluey.

Flatten a dough baton with your palm, then lift it and slap it hard against the bench, fold, slap again. Repeat for 20 sec — each slap stretches the belt a little longer and narrower. When it is an arm's length and a finger wide with a faint ridge down the middle, tear or cut a slit down the centre to make two belts.

⚠ Tip: Slap with confidence: the bang is what stretches the dough. A faint hole or ragged edge is fine — that is what gives the noodles grip.

Drop the belts straight into the boiling water. Cook for 3 min, until they float, turn opaque and chew springy but tender. Scoop them out with a spider, drain and divide between warm bowls. Drop 300 g Baby pak choi into the same boiling water for 1 min, until the stems are just tender and the leaves wilted. Lift them out and scatter over the noodles.

⚠ Tip: Fresh belts cook fast — pull one early and bite it. Soft, not mushy; doughy means another minute.

Pile the minced garlic, ginger and scallion onto the noodles, spoon the chilli-and-vinegar mixture over them, then heat 120 ml Roasted rapeseed oil in a small pan until it shimmers and just begins to smoke. Pour it over the chilli in one steady stream — it should hiss, foam and smell toasted, never acrid or black.

⚠ Tip: Smoking-hot oil, dry chilli: pour from a height and keep the bowl at arm's length. If the chilli smells burnt rather than fragrant, the oil was too hot.

Scatter the rest of the ground Sichuan pepper and tear in the Coriander if you have it. Toss the noodles hard from the bottom so every belt is slicked in chilli oil, and eat immediately while they are warm, chewy and angry.