shred fingered citron and carrot, cut off the roots of Flammulina velutipes, separate them slightly, add Flammulina velutipes to boil the water in the pot, soak it in cold water or ice water for a while, drain the water, and let it cool for later use. Add fingered citron to boil the water in the pot and blanch it for a few tens of seconds. Take it out and soak it in cold water or ice water for a while, drain the water, let it cool for later use, heat a little oil in the pot, add carrots and stir-fry until cooked, take it out and let it cool, put all the ingredients together, add proper salt, sugar, soy sauce, vinegar, sesame oil and mustard oil (not too much, otherwise the taste will be too strong).