Prep your fish by gently rubbing with sake, or cold water. Pat very dry.
Optional: Sake to clean fish
In a mixing bowl, combine the miso paste, mirin, and a bit of honey. Whisk until well combined to create the miso marinade.Set aside two tablespoons of marinade for basting later on. 3 tablespoons miso paste - white or brown, 2 tablespoons mirin, 2 tsp honey
Place the cod fillets on a platter or cutting board, coating the top and sides of the filets with the miso mixture. Do NOT coat the bottom. Then, very lightly sprinkle some pepper on the tops and bottoms of the filets. 1 lb fillets of wild Pacific cod, pepper
Cover the cod and let the cod marinate in the refrigerator for 15-20 minutes, allowing the flavors to meld.
Preheat your air fryer to 415°F (200°C) for 8 minutes.
Remove the marinated cod fillets from the refrigerator. Remove excessive marinade. It should be a thin layer. Place the fillets on parchment paper, in the air fryer basket, making sure they are not overlapping and they are spaced apart.
Air fry the cod fillets for 8 minutes, baste with extra miso marinade sauce, then broil for 2-4 minutes ensuring they are not burning on top. They should be browning and turning golden on top.Once the cod is cooked, carefully remove it from the air fryer using tongs and transfer it to a serving plate. Garnish the air fryer miso cod with thin sliced green onions and sesame seeds, if desired, and serve immediately.
Optional: thin sliced green onions and sesame seeds for garnish