Biang Biang Noodles with Sizzling Chilli Oil

Mix and knead the dough. Stir the flour and salt together, then work in the water and 1 tbsp of oil until a rough dough forms. Knead by hand for 10-12 minutes, or 8-10 minutes in a stand mixer with the dough hook, until it turns smooth and satiny rather than sticky. This long knead builds the gluten network that will later let the dough stretch paper-thin without tearing.

Rest the dough overnight. Shape the dough into a 22cm log, rub it all over with oil, then wrap it tightly in cling film and refrigerate for at least 12 hours and up to 48. This extended rest lets the gluten relax fully, which is what allows each piece to be pulled out to nearly a metre long later without snapping back.

Divide and rest pieces. About 30 minutes before you plan to cook, cut the log into 6 equal pieces, oil them and cover with cling film to rest for 20 minutes at room temperature. This short warm-up softens the chilled dough just enough to make stretching easier.

Bring the water up. Fill a large pot with 4 litres of water, stir in the 20g of salt and bring to the boil, then turn the heat down to keep it hot rather than rolling. Having the water ready means each noodle can go in within seconds of being stretched and torn.

Stretch each noodle. Working on an oiled worktop one piece at a time, flatten the dough to roughly 18 x 8cm, then hold the short ends and stretch it out, bouncing the middle gently against the surface, until it's about 80-90cm long and 2-3mm thick. If a piece springs back or resists, let it rest for 10 minutes and come back to it, since overworked gluten needs a pause before it will stretch further.

Tear into noodles. Pinch the centre of the stretched dough and pull it apart lengthways to open it into a long loop, then cut through the loop to give two noodles. Lay the finished noodles apart on the oiled worktop and cover with cling film so they don't dry out or stick together while you shape the rest.

Blanch the pak choi. Bring the salted water back to a full boil and drop in the pak choi leaves for 30 seconds, just long enough to wilt and brighten them, then lift out and divide between the four serving bowls. A very brief blanch keeps the leaves crisp rather than limp.

Boil the noodles. Cook the hand-pulled noodles in two batches, about 45-60 seconds each, until they rise to the surface and feel chewy-tender rather than doughy in the middle. Lift them straight into the bowls on top of the pak choi with a spider strainer.

Pile on the aromatics. Scatter the chilli flakes, chopped garlic, sliced spring onions and ground Sichuan pepper evenly over the warm noodles in each bowl. Keeping them raw at this stage means the hot oil poured over next will be the only thing that cooks them.

Pour over sizzling oil. Heat the oil in a small saucepan until it shimmers and just begins to smoke, around 200°C, then carefully spoon it over the aromatics in each bowl so they crackle and release their fragrance. This brief blast of very hot oil blooms the chilli's colour and flavour and takes the raw edge off the garlic.

Season, toss and serve. Spoon the soy sauce, black vinegar and sugar into each bowl, then toss everything together at the table so the noodles pick up the oil, spices and seasoning. Eat immediately while the noodles are still warm and the oil is fragrant.