Step 1

In a medium sized bowl combine the tuna, mayonnaise, celery, red onion, dijon mustard, parsley, salt and pepper.

Step 2

Butter each slice of bread. Putting the butter side down add the cheese on the unbuttered side. Add the tuna mixture on top. Top with tomato and additional cheese.

Step 3

Preheat a skillet to medium heat. Add the sandwich on the skillet and heat for about 2-3 minutes until cheese starts to melt and it is golden brown. Flip to the other side and cook until the cheese is fully melted and sandwich is golden brown.

Step 4

Preheat a broiler. Spread the bread butter side up and toast for a couple of minutes. Top with cheese, tuna mixture and Broil for 2-3 miutes until cheese is melted.