Prep the air fryer. Preheat your air fryer to 400°F (200°C) for 3–5 minutes. Lightly spray the basket or line it with a perforated parchment sheet to prevent sticking.

Pat the cod dry. Use paper towels to remove surface moisture. Dry fish browns better and doesn’t steam.

Mix the blackening rub. In a small bowl, combine paprika, garlic powder, onion powder, thyme, oregano, cayenne, brown sugar (if using), salt, and black pepper. Taste a pinch to gauge heat level.

Oil and season. Rub the cod lightly with oil on all sides. Coat generously with the spice blend, pressing it onto the surface so it sticks. Use all the rub for big flavor.

Arrange in the basket. Place fillets in a single layer with space between each piece for air flow. If your fillets are very thin, reduce time slightly.

Air fry. Cook at 400°F (200°C) for 7–10 minutes, depending on thickness. The fish is done when it flakes easily with a fork and reaches an internal temperature of 145°F (63°C).

Finish and serve. Let rest for 2 minutes. Squeeze lemon over the top and garnish with herbs. Serve with rice, roasted veggies, or a simple salad.