A quick but classic recipe from ” Melts” by Fern Green. I also like like to do make this on toasted seeded bagels and then pop it under the grill until the cheese melts.
Mix together the tuna, spring onion, celery, mustard, mayonnaise, oil and lemon juice in a bowl and season.
Butter one side of each slice of bread and turn them over so the butter-side is facing down.
Spread half of the tuna mixture onto one slice of the bread and the rest on another slice. Divide the grated cheese over the tuna mixture, then place the remaining slices of bread on top with the butter on the outside.
Heat up a frying pan over a medium heat and lay each sandwich in the pan. Fry for about 3 minutes on each side or until golden and the cheese has melted.