This is a classic Japanese fish marinade that is quick and simple to make. The miso lends a bit of sweetness to complement the buttery taste of the black cod.
2/3 cup white miso
1/3 cup mirin
1/3 cup sake
1 tablespoon soy sauce
3 tablespoons sugar
2 teaspoons fresh ginger root, peeled and finely grated
4 Black Cod fillets (about 6 oz each)
To make the miso glaze, in a small saucepan combine the white miso, mirin, sake, soy sauce, sugar and ginger. Stir to combine and then bring to a low simmer. Allow to simmer for a few minutes and then remove from heat and let stand until cool. If you’re making the dish ahead of time, you can marinate the fish in the glaze overnight or even a few days ahead of time.
Preheat oven to 450F
When ready to cook the fish, cut 4 pieces of parchment paper into 12-inch sheets, folded to make a “pocket” for the fillet. It may help to make a heart shape with the paper.
Coat each fish fillet completely in the marinade and then place the fillet in the center on the sheet near the fold. Drizzle with additional marinade and then make overlapping folds along the edge of the parchment paper so that you’re sealing the cod fillet inside. Repeat the process for the remaining fillets. Place on a baking sheet and brush the top of the parchment with olive oil. Bake for 15-20 minutes.
Remove from oven, slit open the top of the parchment paper and serve immediately.