Mince the green onion and ginger finely.

Remove the skin and bones from the mackerel fillets and chop the flesh finely with a knife.

Wrap the firm tofu in kitchen paper and microwave at 600W for 1 minute. Let it cool.

Combine mackerel, tofu, green onion, ginger, and potato starch in a bowl and mix well.

Shape the mixture into 6 oval patties and wrap each with a shiso leaf.

Heat salad oil in a frying pan, place the patties, and cook over medium heat until browned. Flip and cook for another 3 minutes until fully cooked.

Mix ponzu sauce and grated ginger in a separate bowl to prepare the dipping sauce.