Saba no Misoni

Ingredients

• 2 mackerel fillets (about 350g total), or 4 pieces of cut mackerel
• 3 tbsp red or awase miso
• 150ml water
• 100ml sake
• 2 tbsp mirin
• 1.5 tbsp caster sugar
• 1 tbsp soy sauce
• 25g fresh ginger
• 2 spring onions
• Boiling water, for blanching

Before you cook

• Cut each mackerel fillet in half crossways so you have four pieces.
• Score a shallow cross in the skin of each piece, which helps the seasoning get in and stops the skin shrinking.
• Peel the ginger and cut half of it into thin coins, then shred the other half into fine needles and soak those in cold water.
• Cut the spring onions into 4cm lengths.
• Lay the mackerel skin side up in a colander and pour boiling water over it for 3 seconds, then plunge it into cold water and pat it dry, because this single step removes almost all the fishy smell.

Steps

1. Put the water, sake, mirin, sugar and soy sauce into a wide shallow pan and add the ginger coins.
2. Bring the liquid to a rolling boil over high heat.
3. Lay the mackerel pieces in the pan skin side up in a single layer, without letting them overlap.
4. Bring the pan back to a boil and skim off any foam.
5. Cut a circle of baking paper the width of the pan, pierce a hole in the middle and lay it straight onto the fish as a drop lid.
6. Simmer over medium-low heat for 7 minutes.
7. Lift the paper and ladle four tablespoons of the hot cooking liquid into a small bowl holding the miso.
8. Whisk the miso and liquid together until completely smooth, with no lumps left.
9. Pour the loosened miso back into the pan around the fish rather than over it, and tilt the pan gently to spread it.
10. Add the spring onion lengths, replace the paper lid and simmer for 6 more minutes without ever letting it boil hard, since boiling drives off the miso's aroma.
11. Take off the lid and spoon the sauce over the fish repeatedly for 2 minutes until it thickens enough to coat the skin.
12. Lift the mackerel onto plates with a fish slice, spoon the glossy sauce over, and top with the drained needles of raw ginger.