Step 1: Pat the Fillets Dry: Press the cod thoroughly dry with paper towels (cod holds a lot of water; skip this and the panko won't stick and the fish falls apart). Check for and pull any bones.
Step 2: Press Into Seasoned Panko: Mix the panko with the lemon zest, dill, black pepper, and garlic powder. Brush both faces of each fillet with a thin layer of olive oil, then press into the seasoned panko (press lightly so it adheres).
Step 3: Load the Basket: Line the basket with parchment. Lay the fillets panko-side up, flat, with no overlap. Set the air fryer to 190°C (375°F) for 12 minutes.
Step 4: Watch the Color: At 7 minutes, pull the basket out: when the panko is golden and the fish turns white, it's done (cod cooks fast — don't let it over-dry and crumble). A fork should separate it easily.
Step 5: Finish and Serve: Lift the fillets out, squeeze lemon over the top, and lay on lemon slices. Rest 1 minute before gently separating — cod is delicate and breaks apart easily.