This retro classic literally melts in your mouth and is super easy to make.
Heat the grill. Start by toasting your baguette under the grill, but keep an eye on it!
Meanwhile, mix the tuna, mayonnaise and spring onion in a bowl.
Once your baguette is on its way to being nicely toasted, remove from under the grill. Spoon the tuna mix onto the top of the baguette. Top with the tomato slices and finally the grated cheddar cheese.
Put back under the grill until the cheese is bubbling and golden. This should take about 5 minutes.
Remove and serve with a fresh green salad for a tasty lunch in minutes – delicious!