Step 1

Drain the tuna then place in a mixing bowl.

Step 2

Add finely diced onion and celery, mayonnaise, lemon juice and all the herbs and spices.

Step 3

Mix well, taste and adjust seasoning if necessary. Place slices of bread on a sheetpan then toast under a hot grill/broiler.

Step 4

Flip over then top half the slices with tuna filling, cheese and sliced tomatoes.

Step 5

Place back in the oven and allow the cheese to melt.

Step 6

Remove from the oven, sandwich with the remaining slices of bread and serve.