Step 1

If using butter, let 2 tablespoons unsalted butter sit at room temperature to soften. Meanwhile, make the tuna salad.

Step 2

Prepare the following, adding each to the same medium bowl as you complete it: Finely chop 1/2 small shallot (about 1 tablespoon). Finely chop 1 medium celery stalk or scallion. Finely chop 1 dill pickle spear (2 heaping tablespoons). Drain 1 (5-ounce) can oil- or water-packed tuna fish well.

Step 3

Add 1/4 mayonnaise and use a fork to break the tuna down into flakes and mix everything together. Add 1/8 teaspoon kosher salt, 1/8 teaspoon black pepper, and the juice from 1 lemon wedge. Mix with the fork until combined.

Step 4

Heat a large skillet over medium-low heat. Meanwhile, assemble the sandwiches.

Step 5

Cut 1 large tomato crosswise into 1/4-inch thick slices. Spread the butter or 2 tablespoons mayonnaise evenly onto 1 side of 4 sandwich bread slices. Flip 2 of the slices over. Top each one with 2 sharp cheddar cheese slices. Top with the tomato slices. Divide the tuna salad over the tomatoes and spread into an even layer. Close the sandwiches with the remaining 2 bread slices buttered-side up.

Step 6

Place the sandwiches in the skillet and cook until golden brown and the cheese is melted, 3 to 4 minutes per side. Transfer to a plate or cutting board and cut the sandwiches in half before serving.