The beauty of this dish is its simplicity. It only has five ingredients, but each plays a vital part in the recipe. The miso adds flavor, the sake and mirin season the fish, and the mayo promotes the development of a beautiful browned finish on the salmon.
Whisk together the miso, Kewpie mayo, sake and mirin in a small bowl. Coat the entire salmon fillet in the mixture and marinate for 20 minutes.2.
Preheat the oven to 350 F.3.
Line a baking sheet with a wire rack or piece of foil, then place the salmon on top, skin side down. Bake for 3-5 minutes, depending on the thickness of the fillet (3 minutes for a 1-inch-thick fillet; 5 minutes for a 2-inch piece).4.
Turn on the broiler and adjust the oven rack so that the fish sits about 6 inches below the heat source.5.
Cook for 4-5 minutes more, until the fish is nicely browned and just cooked through.