Otherwise known as saba misoni.
Slightly tweaked by me, with the addition of a soft poached egg on top. Methinks the runny yummy yolk can only add to the tastiness of any dish, no?
Blanch prepped mackerel fillets in nearly boiling water to ‘cleanse’ them. This helps getting rid of some of the strong fishy smell some people can’t seem to take.
Then combine some water, miso paste (akamiso is my preference), sake, sugar (maple syrup, or honey, anything sweet really) and mirin in a pan. Bring to a light simmer.
Add in the green tops of spring onions and ginger, and give it a little stir. Place fish gently into pan, skinside up and pop a lid on. Simmer on low for about 10 minutes.
While waiting, poach an egg.
Assemble when everything is cooked, and finishing the dish with strips of green onion whites and bonito flakes.
The quantity of each ingredients are up to your own tastes and preference.