In a bowl or glass pie plate just large enough to hold the fish, whisk together the miso, maple syrup, mirin, ginger and sesame oil.  Place the fish in the bowl and spoon the marinade on top of the fish to cover it completely.  Cover the bowl with a plate and marinate in the refrigerator for at least 30 minutes or overnight.  The longer you can do this, the better the fish will taste.

Before cooking the fish, preheat the broiler and position your oven rack about 6 inches from the heat.  I place the rack on the level the second from the top.

If you don’t have a stainless steel baking sheet, line a baking sheet with unbleached parchment paper.

Pull the fish from the bowl and shake off any excess marinade clinging to the fish.  Place the fish on the baking sheet and broil until the glaze is dark and shiny and the fish flakes when you press on it, about 6-8 minutes.