1-Step 1: Mixing the Tuna Filling: Start by combining the ingredients in a large bowl. Mix 4 cans of drained solid white albacore tuna, 2/3 cup of full-fat mayonnaise, 2 small diced ribs of celery, 1 finely minced garlic clove, 1 tablespoon of finely minced capers, 1 small diced dill pickle, 1/2 small diced red onion, 1 tablespoon of finely minced fresh dill, and the juice of 1/2 lemon. Season with coarse salt and freshly cracked pepper to taste until everything is well combined. This step takes about 10 minutes and lets the flavors meld together.

2-Step 2: Heating and Toasting the Bread: Heat 1 tablespoon of unsalted butter in a griddle or large skillet over low to medium heat. Toast 4 slices of bread for about 2 minutes until they turn golden, then flip them. Add another tablespoon of butter to the pan for extra crispiness, and place a slice of cheese on each toasted slice.

3-Step 3: Assembling and Cooking: Spread the tuna mixture evenly on two of the cheese-topped slices. Cook for another 2 minutes to melt the cheese. Then, place the remaining toasted slices with cheese on top of the tuna-covered ones, cheese side down. Remove from heat and slice each sandwich in half. Repeat the process to make the other two sandwiches, which takes about 8 minutes total.