Scrape the pigskin, blanch it in boiling water, take it out, wash it with ginger, pat it loose, put it in a casserole with the blanched pigskin and onion, pour in water (without the skin), cinnamon, pepper and star anise, boil it with strong fire, remove the foam, and simmer with low fire until the skin can be pinched, leaving the original soup. Cut the boiled skin into small pieces and put it in the pot. Add the original soup, salt, cooking wine, soy sauce and monosodium glutamate, collect the soup with medium fire, cool and freeze. You can slice and dice when you eat. A bowl of transparent pigskin jelly came out.