1. Grind Redmi into powder, put it in a tea bag, put it in a pot and pour it into boiling water. When the lid is covered and soaked until it is not hot, gently knead to fully dissolve the pigment until the red rice flour in the bag becomes sticky, that is, Redmi water;

2. Wash the pork belly and put it in the pot. Add water and Redmi water and stir, without meat. After the fire boils, skim all the floating foam, add ginger slices and onion knots, cover and cook for half an hour, so that the meat is colored, which is "red water";

3. Take out the colored meat pieces, rinse them with clear water, change knives and cut them into 4cm square pieces; Prepare another pot (preferably a non-stick pot), put a flat plate (preferably a bamboo pad) at the bottom of the pot, and put the meat pieces upright in the middle of the pot with the skin facing up;

4. Add soy sauce, Shaoxing wine and "red water" soup to make the meat pieces completely immersed, boil with strong fire, and continue to cook with medium fire for about 1 hour; Add rock sugar and salt and cook for another half an hour. At this time, the meat is cherry-colored, and the juice is collected until it is thick and gelatinous.