I've adapted this from Elizabeth Andoh's wonderful book Washuko. I love the flavors in Japanese food, and how simple most of the recipes are. This one is no exception; beautiful fresh fish, miso, mirin and sake. That's it.
Remove the fish from the refrigerator, and salt it lightly. Set aside while preparing the miso mixture.
Combine the miso, mirin and sake in a small bowl, mixing until well combined.
Pread the miso mixture on all sides of the fish (except the skin side) and set aside for 20 minutes at room temperature. If your kitchen is very warm (summer, heat wave), you could refrigerate for up to an hour.
Preheat your broiler, setting the rack so that your fish will be about 3 inches below the heat source.
When hot, broil the fish for 5-6 minutes, until the miso glaze is golden brown, and the fish is cooked through.