Put the cornflakes into a plastic bag, crush using a rolling pin and spread out onto a plate. Cut the fish into 6 strips and season with salt and pepper. Coat with flour. Dip into the lightly beaten egg and then coat with the crushed cornflakes.
Heat the oil in a frying pan and sauté the fish for 3 to 4 minutes or until golden and cooked through. Turn halfway through.
To make the tartare sauce, simply mix all the ingredients together and serve with the fish.