Drain the tuna well and transfer to a bowl. Separate into large flakes with a fork
Add the chopped onion, chilli and tomatoes and mix well
Mix in the mayonnaise and add some pepper
Spread some butter on both sides of the bread. Toast the bread in a non-stick pan
Spread the filling on the bread. Sprinkle some cheese over and place the bread on a baking tray. Pop it under the grill in the oven until the cheese melts
Notes
You can use either mozarella, swiss or cheddar cheese for the Tuna Melts. I did not add too much cheese because I have to watch what I eat. But you can add as much cheese as you wish.
The filling for this can be made ahead of time and kept in the refrigerator. When you are ready to serve you can toast the bread, pop on the filling and grill them
To make these sandwiches go further in these tough times you can pop another slice of bread on top of each sandwich and serve a family of four