Step 1

Drain water from tuna and put the tuna into a medium bowl.

Step 2

Chop onion, celery, and parsley. Mince garlic and add ingredients to tuna.

Step 3

Add mayonnaise, olive oil, and mozzarella cheese. Combine all ingredients until well incorporated. Salt and pepper to taste.

Step 4

Place a non-stick skillet on the stove and add 1 tablespoon of olive oil. When the skillet is hot, take a slice of bread and generously spread butter on one side.

Step 5

Place the bread (buttered side down) in the hot skillet.

Step 6

Using a spoon, scoop about 2 tablespoons of tuna salad on bread while it is browning.

Step 7

Butter another slice of bread with butter and place non-buttered side on top of tuna.

Step 8

Using a spatula, check to see if the bread is toasted brown. If so, turn the tuna melt over and grill the other side until it's golden brown.