Half Tuna Melt Recipe

Make tuna filling

In a small bowl, flake the drained tuna with a fork. Add mayonnaise, finely minced red onion, finely diced celery, lemon juice, and Dijon mustard. Stir to combine into a slightly chunky, spreadable mixture. Season with salt and black pepper, taste and adjust seasoning as needed.

Assemble sandwich

Lay two slices of marble rye on a clean work surface. Spread the tuna mixture evenly over one slice, leaving a small margin at the edges. Top the tuna with the slice of pepperjack cheese. Close with the second slice of bread, pressing gently.

Butter and cook

Heat a nonstick skillet or griddle over medium heat. Evenly spread the softened butter on the outside faces of both bread slices (or on the skillet if preferred). Place the sandwich in the skillet and cook 3–4 minutes per side, pressing lightly with a spatula, until bread is golden brown and cheese is melted. If the bread is browning too quickly before the cheese melts, reduce heat to medium-low and cover the pan for 1–2 minutes to help melt the cheese.

Slice and serve

Remove the sandwich from the skillet and let rest 1 minute. Cut the sandwich in half (for a half tuna melt order, serve one of the two halves) and serve immediately.