Prep the fish: Pat the fish dry with paper towels. Cut into even sticks about 1 inch wide and 3–4 inches long.
Season lightly with salt and pepper.
Heat the oven or air fryer: For the oven, preheat to 425°F (220°C). Line a sheet pan with parchment and place a wire rack on top if you have one. For the air fryer, preheat to 400°F (205°C).
Set up breading station: In one shallow bowl, add flour.
In a second bowl, whisk eggs, mayonnaise, and Dijon until smooth. In a third bowl, combine panko, Parmesan, garlic powder, onion powder, paprika, 1/2 teaspoon salt, and 1/4 teaspoon pepper.
Bread the fish: Dredge each stick in flour, shaking off excess. Dip in the egg mixture, letting extra drip back into the bowl.
Press into the panko-Parmesan mixture, coating all sides. Place on the prepared rack or a plate.
Add a little oil: Lightly brush or spray the tops with oil. This helps achieve a golden, crispy crust.
Cook (oven method): Bake for 12–15 minutes, flipping halfway and lightly oiling the other side, until golden and the fish flakes easily.
Thicker pieces may need up to 18 minutes.
Cook (air fryer method): Arrange in a single layer and cook 8–10 minutes, flipping once. Work in batches if needed. They’re done when crisp and flaky.
Optional pan-fry: Heat a thin layer of oil in a nonstick skillet over medium heat.
Cook 2–3 minutes per side until golden and cooked through.
Finish and serve: Sprinkle with a pinch of salt while hot. Serve with lemon wedges and your favorite dip.