1. Cut the scallion into powder, fry it in oil until crisp, and take it out for later use, leaving no residual oil;

2. Clean mackerel, cut it in half with a knife, remove fat and red impurities, wash it again and dry the water;

3. Scrape the fish with a knife, leaving only the skin. If there are small thorns on the fish, try to pick them out;

4. Put the fish in a container, add appropriate amount of salt, chicken essence and pepper, and then rub some ginger with a spatula;

5. Knead with your hands in the same direction until the fish paste is gelatinous and sticky;

6. Add crispy chopped green onion and appropriate amount of sweet potato powder;

7. Knead evenly by hand until there is no powder;

8. Put a little oil in the pot, stir-fry the minced chives, then pour in clear water, add ginger slices, bring some fish paste in your hand after the water boils, squeeze some balls out of the tiger's mouth and cook them in the pot until the fish balls come out;

9. Add noodles and boil;

10. Add small vegetables and cook, add salt, chicken essence and pepper, sprinkle some chopped green onion before taking out, and a delicious fish ball noodle soup is ready.