1. Crush the ginger and scallion with the flat side of a cleaver blade or a heavy object and leave to soak for 5-10 minutes in ¼ cup of cold water.
2. Make the stuffing: place the pork in a bowl. Add the fragrant soaking water from the ginger and scallion, discarding the pieces, and mix well until it has been absorbed. Gradually pour in the chicken stock, mixing well to allow the pork to absorb it. You should end up with a loose, moist stuffing. Add all the seasonings and mix well.
3. Make the pastry: Combine the flour and salt in a large mixing bowl and make a well in the center. Bring the water to a boil, remove it from the heat to let it stop bubbling, and then pour it onto the flour. Mix in quickly with the handle of a wooden soon. When the mixture is cool enough to handle, transfer it to a work surface and knead to a smooth dough.
4. Make the wrappers: working on a lightly floured surface, break the dough into two or three pieces. Roll each one out into a sausage about 1 inch thick. Break off teaspoon-sized pieces and flatten them with the palm of your hand. Roll the flattened pieces into circles about 2 ½ inches in diameter. (Unless you are working very quickly, it’s a good idea to cover the remaining dough with a damp kitchen towel to pre vent it from drying out).
5. Place about a teaspoon of stuffing into the center of each dumpling skin. Fold the skin gently in half and, starting at one end, join the two sides together with a series of pinches. Place the finished dumpling on your work surface, pushing it slightly to give it a flat base.
6. Cook the dumplings: heat a heavy, flat-bottomed frying pan or skillet over a medium flame. Pour in enough lard or peanut oil to coat the surface generously. When the oil is hot, arrange all the dumplings in the pan in neat rows. Drizzle them with warm water – 2-3 tablespoons for every 5 dumplings. Cover the pan with a lid and steam over a medium heat for 4-5 minutes. Then remove the lid to allow the steam to escape, drizzle the dumplings with a little oil (about ½ tablespoon for every 5 dumplings), replace the lid, and fry for 2-3 minutes more, until their bottoms are toasty and golden brown. As the dumplings cook, move the pan around the hot plate to brown them evenly. To serve, remove them with a spatula and turn them upside down onto a serving plate, so you can see their golden bottoms. Serve immediately.