Heat the air-fryer to 180C. Cut the fish into 3-4cm-thick lengths (the size of a classic fish finger) – you should be able to make around 6-8. Tip the beaten egg onto a plate or into a shallow bowl. Tip the panko breadcrumbs onto another plate or into a shallow bowl and season well.

Roll the fish pieces in the egg, gently shake off any excess, then coat in the panko breadcrumbs. Transfer the coated fish to a plate and continue with the remaining pieces.

Transfer the fish fingers to the air-fryer basket, keeping them in a single layer, then cook for 8-10 mins until cooked through and golden.

To make a sandwich, butter two slices of bread, then spread a thick layer of the tartare sauce or ketchup over one piece. Lay 3-4 fish fingers on top, followed by a few lettuce leaves, then top with the second slice of bread.