Drain the tuna and add it to a large bowl. Flake it with a fork to break it up.
4 cans 5 ounce tuna packed in water
Chop the celery, red onion and parsley (if using). Mince all the vegetables finely and stir into the bowl with the tuna.
1/4 cup celery, 2 Tablespoons red onion, 1 teaspoon parsley
Set the air fryer to preheat at 370 for 2 minutes while you finishing making the tuna salad.
Add the mayonnaise, mustard and lemon juice to the bowl and mix. Start with the smaller 1/2 cup amount of mayonnaise. If it doesn't look creamy enough after mixing add another 1/4 cup of mayonnaise and mix again.
1/2 - 3/4 cup mayonnaise, 1 teaspoon mustard, 1 Tablespoon lemon juice
Season with salt and pepper to taste.
salt and pepper to taste
Put 2-4 Tablespoons of the tuna salad mixture on your bread or roll of choice. The amount you use will depend on the size of your bread. Mound it up a bit in the middle.
Ciabatta rolls
Put the open faced sandwich in air fryer. Do not add the cheese yet! Air fry the open faced tuna melt at 370 for 3-4 minutes. Use the shorter time for thin bread or English muffins and the longer time for rolls. You can add the English muffin top or top of the roll to the basket to toast along with the tuna melt. This will decrease the number of sandwiches you can fit in at one time though.
After the cooking time is up open the basket and add a slice of cheese on top of the tuna melt. Close the basket and the residual heat from the air fryer will melt the cheese onto the tuna. If you want your cheese very melted you can air fry it at 350 F for another minute.
Cheddar cheese slices
Serve open faced or with a top along with sliced tomatoes, avocados or pickles.
Tomato slices, parsley
Notes
This recipe makes enough for 6-8 tuna melts, depending on what bread you use.