1. Wash the golden ham slices in warm water for later use.
2. Remove the roots of seafood mushrooms and crab-flavored mushrooms and wash them.
3. Cut old tofu into small pieces.
4. Heat oil in a pan and stir-fry the mushrooms.
5. Put ham and tofu in turn, add water to a boil over high heat, simmer for 20 minutes on low heat, and sprinkle with chopped green onion before serving.