1. Cut the crusts off the slices of sandwich loaf and grind them in a food processor to obtain soft bread crumbs. Place the bread crumbs in a bowl, add the well-drained, flaked tuna, the finely chopped spring onion and parsley, the mayonnaise, the mustard and the egg and mix the ingredients together.
2. Form hamburger patties with the mixture, heat a lightly-oiled non-stick frying pan over a high flame until it is good and hot and then lower the hamburgers into it. Cook the burgers on both sides, turning them with a spatula, to ensure a uniform thickness. The burgers are cooked when they turn a golden brown colour.
3. Serve immediately with tasty potato chips cut into large segments
