Instructions

1. Mix the miso paste, mirin, sake, and sugar in a bowl to create the marinade.

2. Marinate the black cod fillets in the mixture for at least 2 hours, or overnight for best flavor.

3. Preheat the oven to 400°F (200°C).

4. Wipe off excess marinade and place the fillets on a baking sheet.

5. Bake for 10-12 minutes, until the fish is opaque and flaky.

6. Optionally, broil for 1-2 minutes for a crispy top.