3 tablespoons mirin
3 tablespoons sake
1/2 cup white miso paste
1/3 cup sugar
Six 6- to 7-ounce skinless black cod fillets, about 1 1/2 inches thick
Vegetable oil, for grilling
Pickled ginger, for serving
Instructions
In a small saucepan, bring the mirin and sake to a boil.
Whisk in the miso until dissolved.
Add the sugar and cook over moderate heat, whisking, just until dissolved.
Transfer the marinade to a large baking dish and let cool.
Add the fish and turn to coat. Cover and refrigerate overnight.
Preheat the oven to 400°.
Heat a grill pan and oil it. Scrape the marinade off the fish.
Add the fish and cook over high heat until browned, about 2 minutes.
Flip the fish onto a heavy rimmed baking sheet and roast for 10 minutes, until flaky.
Transfer to plates and serve with pickled ginger.
MAKE AHEAD The marinade can be refrigerated for up to 1 week.