This sweet and silky fish dish from Nobu New York has been cloned at restaurants all over the country. It's fairly straightforward to make. The fish marinates overnight in just enough sake and miso to coat. Quickly searing the cod, then finishing it in the oven, creates a beautifully burnished crust.
In a small saucepan, bring the mirin and sake to a boil over high heat. 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 degrees.
Heat a grill pan over high heat and coat with vegetable oil. Scrape the marinade off the fish. Add the fish and cook until browned, about 2 minutes. Flip the fish onto a heavy rimmed baking sheet and roast until flaky, about 10 minutes. Transfer to plates and serve with pickled ginger and sautéed baby bok choy.