Tuna Melt Baguette Recipe

Open and drain the canned tuna thoroughly. Transfer tuna to a medium mixing bowl and break up any large chunks with a fork.

Add mayonnaise, Dijon mustard, lemon juice, chopped capers, and chopped parsley to the bowl. Stir until combined and mostly smooth.

Fold in the finely diced celery and red onion. Season with salt and black pepper, tasting and adjusting seasoning as needed. Set the tuna salad aside while you prepare the baguette and cheese.

Preheat your broiler to high (or heat oven to 450°F / 230°C with the top rack about 6–8 inches from the heat source).

Slice the baguette horizontally lengthwise to create a top and bottom. If desired, cut into two 6-inch sections for easier handling (this recipe makes about two sandwiches).

Spread the cut sides of the baguette with softened butter (about 1 tbs per side). Place the baguette open-faced on a baking sheet, buttered side up.

Toast the buttered baguette under the broiler 1–2 minutes until lightly golden and crisp — watch carefully to avoid burning. Remove from oven.

Layer tomato slices across the bottom half of the toasted baguette, then add a thin layer of the reserved thinly sliced red onion if using. This prevents the bread from getting soggy and adds flavor.

Spoon the prepared tuna salad evenly over the tomato layer, spreading to the edges but not mounding too high (about 6 oz of tuna filling per 6-inch sandwich).

Arrange the shredded or sliced cheddar (and optional Swiss/provolone) evenly over the tuna. The cheese should cover the tuna in a single layer to melt uniformly.

Place the baking sheet under the preheated broiler for 2–4 minutes until the cheese is melted and bubbly and the edges begin to brown. Alternatively, bake at 450°F for 5–7 minutes until cheese is melted.

Remove from oven and let rest 1 minute. Sprinkle with chopped parsley or chives for color.

Close the sandwich with the top half of the baguette, press gently, and slice into serving portions (two or three pieces). Serve immediately while the cheese is hot and melty.