Black cod is steeped in sweet miso before being baked in the oven. The sweetness of the Nobu-style saikyo miso is an excellent match with the plumpness of the fish.
Taken from Nobu the Cookbook.
Firm and oil-rich fish works well with this recipe. You can substitute black cod for salmon (which I often do for economical reason), Chilean sea bass (but maybe you should not, for ecological and ethical reasons) or snow fish (which might just be the synonym for black cod in Asia, I'm not sure exactly). Apparently you can do this for beef too, although I have never tried.
To make the marinade/sauce:
1. Bring the saké and mirin to a boil in a medium saucepan over high heat. Boil for 20 seconds to evaporate the alcohol.
2. Turn the heat down to low and add the miso paste, mixing with a wooden spoon. When the miso has dissolved completely, turn the heat up to high again and add the sugar, stirring constantly to ensure that the bottom of the pan doesn't burn. Remove the heat once the sugar is fully dissolved. Cool to room temperature. Yields 3 cups.
For the fish:
1. Pat the fillets thoroughly dry with paper towels. Slather the fish with the marinade, place in a bowl and cover with plastic wrap. Leave in refrigerator for 2 to 3 days.
2. Preheat the oven to 400°F (200°C). Preheat a grill or broiler. Lightly wipe off any excess miso clinging to the fillets but don't rinse it off. Place the fish on the grill, or in a broiler pan, and grill or broil until the surface of the fish turns brown. Then bake for 10 to 15 minutes.
3. Arrange the black cod fillets on individual plates and garnish with hajikami. Add a few extra drops of the miso sauce to each plate.
If you would like to learn more about the different types of fish, check out our Fish 101 page.