Remove the skin and bones from the mackerel fillets and scrape off the flesh. Chop the flesh with a knife until sticky.

Slice the shiitake mushroom thinly and cut the carrot into bite-sized pieces (quarter slices).

In a bowl, mix the mackerel with the fish ball seasonings (miso, potato starch, sesame oil, and ginger) to form the fish ball mixture.

In a pot, add dashi powder, water, soy sauce, and salt. Heat over medium heat until boiling.

Scoop the fish ball mixture with a spoon and drop into the boiling broth. Once the fish balls are cooked, add shiitake and carrot. Simmer until the carrot is tender.