How to Make It
Combine the pork, soy sauce, salt, sugar, and 2 tablespoons water in a bowl and mix well. Marinate for 15 minutes.
Meanwhile, make the red oil. Toast the sesame seeds in a small pan over medium heat and shake occasionally for 3–5 minutes, or until golden brown. Set aside.
Mix the ginger, garlic, salt, soy sauce, chili powder, and crushed peppercorns in a small heatproof bowl.
Heat the oils in a small skillet (frying pan) over medium high heat, then pour into the bowl. Stir in the sugar and toasted sesame seeds. Set aside.
To make the filling, bring a large pot of water to a boil, add the cabbage leaves, and blanch for 5 minutes. Drain and rinse under cold running water. Chop the cabbage, squeeze out most of the water, and add to the pork. Mix well. Stir in the cornstarch (cornflour) and the sesame oil. Mix again.
Take a wonton wrapper and lay it flat on a cutting board. Add about 1/2 tablespoon of the filling in the center of the wrapper. Fold into a triangle, then fold the two ends to the center. Seal the folds with a little water. Press the ends tightly and lay on a large plate. Repeat with the remaining wrappers and filling.
Bring a large saucepan of water to a boil over high heat. Add the wontons, in batches, and cook for 3–4 minutes until they float to the surface of the water. Add 1/2 cup (4 fl oz/120 ml) cold water, increase the heat, and return to a boil. Cook the wontons until they float to the surface, then use a slotted spoon to transfer them to a bowl.
Drizzle over the red oil, sprinkle over the crushed peanuts, if using, and scallion (spring onion), and serve immediately.
The wontons can be frozen for up to a month. Spread out the uncooked wontons on a plate, freeze until firm, and then transfer them to a freezer bag. When ready to serve, put the frozen wontons into a saucepan of cold water and bring to a boil over medium-high heat. When the wontons float to the surface, add 1/4 cup (2 fl oz/60 ml) cold water and return to a boil.