Mackerel (fillets, whole fish, anything that isn't canned.)
Japanese soy sauce (can substitute Chinese dark or light, but this recipe dates from a sushi party)- enough to cover fish in a bowl.
You can either leave the mackerel whole (looks better for main courses) or shred it into small pieces (ideal for helping yourself, like at a sushi party).
Chop the spring onions- always include the green parts! and add it to the soy.
Marinade the fish in the soy sauce for quite some time (longer for whole fish).
Sprinkle the seasonings over the fish.
Place it under a hot grill (top shelf, so it will crisp.)
The fish should be cooked through, of course, and thoroughly infused with the soy. It should not be completely dry, but crispy in places. i.e. 'Grilled'.
Sprinkle with the remaining sprongions, and serve.