Marinate the pork: In a large bowl, mix pork mince with salt, white pepper, light soy sauce, dark soy sauce, oyster sauce, and chicken bouillon. Stir in one direction until sticky. Add scallion-ginger-star anise water in 3 batches, stirring thoroughly each time until fully absorbed. Marinate for 15 mins.
Prep the sauerkraut: Rinse sauerkraut 1-2 times quickly, squeeze out ALL excess water (critical!), then chop finely. Add to the marinated pork along with chopped scallions; mix well.
Make fragrant scallion oil: Heat 30ml oil in a pan over low heat. Fry minced ginger and onion until golden and aromatic (don’t burn!). Pour the hot scallion oil + aromatics over the filling; stir quickly to release flavors.
Make the dough: Mix flour with salt (if using). Add warm water in batches, stirring into flakes. Knead into a smooth dough, cover, and rest for 20 mins.
Roll wrappers: Knead the dough again, roll into a log, and cut into 15g portions. Press each into a disk, then roll into 7-8cm wrappers (thicker in the center, thinner at edges).
Wrap the dumplings: Place 25-30g filling in the center of a wrapper. Dampen the edges with water, fold in half, and pinch tightly. Pleat the edges (optional) for a secure seal. Place on a floured plate.
Cook the dumplings: Bring a pot of water to a boil. Add dumplings, gently stir to prevent sticking. When boiling again, add 1 bowl cold water. Repeat 2-3 times until dumplings float and puff up—they’re done!