1. Wash beef, cut into pieces, put it in a boiling water pot, soak it for about 5 minutes, take it out, wash it and drain it. Turtles should also be blanched with boiling water.
2. Peel the yam, wash it, put it in a boiling water pot, take it out and drain it.
3. Wash the casserole, add water, turtle, beef, onion, ginger, cooking wine and celery, boil over medium heat, skim the floating foam, add pepper, simmer over low heat until it is half done, add yam, stew for about 3 hours until the beef is crisp and rotten, take out onion, ginger and celery, and add refined salt, monosodium glutamate and pepper.