Pat the cod fillets very dry with paper towels, then season lightly with salt and pepper.
Set up 3 shallow bowls: flour in the first, beaten eggs in the second, and panko mixed with paprika, garlic powder, pepper, and a pinch of salt in the third.
If using Dijon mustard, stir it into the beaten eggs.
Coat each fillet lightly in flour and shake off the excess.
Dip the floured fillets into the egg mixture and let the excess drip off.
Press each fillet into the panko mixture so the crumbs stick well.
Let the breaded cod rest for 5 to 10 minutes so the coating sets.
Lightly mist the tops with oil spray.
Air fry at 400°F, flipping halfway through, until the coating is crisp and the fish flakes easily.
Cook about 8 to 10 minutes for thin fillets, 10 to 12 minutes for medium fillets, or 12 to 14 minutes for thick fillets.
The cod is done when it reaches 145°F internally.
