Step 1

Drain the tuna. Place it in a bowl and use a fork to break apart any large clumps. Finely chop the red onion and dill pickles, and mince the parsley. Add the vegetables to the bowl with the tuna, along with the dried tarragon or dill, mayonnaise, Dijon mustard and salt. Stir to combine.

Step 2

Spread the outsides of the bread slices with mayonnaise or butter. Assemble the sandwiches: on each slice of bread (buttered side out) place the tuna salad filling, a tomato slice, and 2 slices of cheddar cheese, then top with the other slice of bread.

Step 3

Preheat a skillet over medium heat (cast iron works well if you have it). Cook the sandwich 2 to 3 minutes, then carefully flip and cook about 2 minutes more until browned and the cheese is melted. Serve immediately.