Place the 500g ground pork in a large mixing bowl and add the 2 finely chopped scallions, 2 tsp grated ginger, 2 grated garlic cloves, 1 tbsp light soy sauce, 1 tbsp Shaoxing wine, 1 tsp toasted sesame oil, ½ tsp fine salt, ½ tsp sugar, ¼ tsp ground white pepper and the ¼ tsp ground Sichuan peppercorn, if using. Add the 2 tbsp water or unsalted stock a tablespoon at a time, then stir vigorously in one direction with chopsticks or a sturdy spoon for 1–2 minutes, until the filling looks sticky, slightly elastic and cohesive and starts to pull away from the bowl in strands. It should look tacky and hold together on the spoon; if it still looks loose and crumbly, keep stirring for another 30 seconds. Cover the bowl and let the filling rest for 15 minutes. That one-direction stirring is what works the pork's proteins into a sticky bind that holds the water in and gives the filling its juicy, springy texture.

While the filling rests, combine the 8 tbsp Chinese chili oil, including a good spoonful of the chili flakes or crisp solids from the jar, with the 4 tbsp light soy sauce, 4 tbsp Chinese black vinegar, 2 tsp sugar, the 3 grated garlic cloves and ½ tsp ground Sichuan peppercorn in a small bowl. Stir well to dissolve the sugar as much as possible, then taste: the sauce should be bold, salty, tangy and spicy, with a gentle tingle, before any water goes in. Add a pinch more Sichuan peppercorn if you want a stronger numbing character. Thinly slice the 3 scallions, chop the 15g cilantro and roughly crush the 40g roasted peanuts, then set them out with the 2 tbsp toasted sesame seeds. That fully seasoned base matters because the hot cooking water added later softens it, so it has to start out genuinely assertive.

Set the 32 wonton wrappers under a barely damp towel so they do not dry out, with the small bowl of cold water and a parchment-lined tray beside them. Place a generous heaped teaspoon of filling, about 17g, in the centre of a wrapper. Moisten the edges lightly with a fingertip dipped in the water, fold the wrapper into a triangle and press firmly from the filling outwards to seal, removing any obvious air pockets. Bring the two side corners together and press them to make a classic wonton shape, or leave them as triangles. Repeat to make 32 wontons, arranging them on the tray without letting them touch too much and keeping the finished ones covered. Towards the end of folding, bring the 4 litres of water to a gentle boil in a large pot. That tight, air-free seal is what stops the wrappers from bursting or leaking filling into the water.

Keep the water at a gentle boil, with steady bubbles rather than a violent rolling boil, then drop in the wontons; the pot should be large enough for them to move freely without crowding. Stir gently once along the bottom so none stick. Cook for 4–5 minutes, until the wrappers turn silky and slightly translucent and the filling is fully cooked. The wontons usually float after about 3 minutes, but floating alone is not the doneness cue, so give them another 1–2 minutes after they rise. If unsure, cut one open: the pork should be opaque throughout with clear juices, or read 71°C at the centre. Before draining, scoop out about 120ml of the hot cooking water and keep it beside the sauce. That gentle boil is what lets the pork cook through while the delicate wrappers stay whole and sealed.

Stir 2 tbsp of the reserved hot cooking water into the sauce, then add a little more, a teaspoon at a time, only if needed, until the sauce loosens slightly into a glossy, lightly pooling base rather than a thick paste. The oil and the soy-vinegar mixture should look drawn together rather than sitting in separate layers; if the sauce turns thin, stop adding water rather than diluting its flavour further. Drain the wontons well in a slotted spoon or colander, shaking off the excess water so it does not dilute the sauce. Work quickly, since drained wontons left standing begin to stick together. That hot, starchy cooking water is what helps emulsify the oil into the soy and vinegar, giving a cohesive sauce that genuinely clings to the wrappers.

Spoon about half of the sauce into 4 shallow serving bowls. Divide the wontons among them, 8 wontons per serving, then spoon the remaining red oil sauce over and around them, so it coats the wontons and pools lightly around them without drowning them. Scatter over the sliced scallions, chopped cilantro, toasted sesame seeds and crushed peanuts, then finish each bowl with a little extra chili oil spooned over the top. Serve immediately, while the wrappers are at their silkiest; letting the bowls sit makes the wrappers soften excessively. That last-minute garnishing is what keeps the herbs fresh and bright and the peanuts crunchy against the silky wontons.