Prep the air fryer. Preheat to 390°F (200°C) for 3–5 minutes. Lightly spray the basket with cooking spray to prevent sticking.
Pat the salmon dry. Use paper towels to remove surface moisture.
This helps the crust adhere and keeps the fish from steaming.
Season the fish. Sprinkle both sides with salt and pepper. If the fillets are thick, season a touch more on top.
Make the crust mixture. In a bowl, combine Parmesan, panko, olive oil (or butter), parsley, garlic, lemon zest, and a pinch of pepper. Stir until it looks like damp sand—crumbly but cohesive.
Make the “glue.” In a small cup, mix mayonnaise and Dijon.
Spread a thin layer over the top of each fillet. This is key for keeping the crust in place and the salmon moist.
Top with the crust. Press a generous layer of the Parmesan-panko mixture over the mayo-coated surface. Gently pat so it sticks well.
Air fry. Arrange the salmon in the basket, crust side up, leaving space between pieces. Cook for 7–10 minutes, depending on thickness.
Aim for an internal temperature of 125–130°F (52–54°C) for medium or up to 135°F (57°C) for more done.
Rest and serve. Let the salmon rest 2 minutes. Finish with a squeeze of lemon and a sprinkle of fresh herbs. Serve hot.