Tuna Salad Sandwich Recipe

Prepare tuna

Open and drain the canned tuna well. Transfer tuna to a medium mixing bowl and use a fork to flake it into small chunks.

Add mayonnaise, Dijon mustard, lemon juice and chopped capers to the flaked tuna. Stir gently to combine until evenly coated.

Fold in finely diced red onion, diced celery and chopped parsley. Season with salt and black pepper. Taste and adjust seasoning or lemon as needed. Cover and refrigerate for at least 10 minutes to let flavors meld (up to 1 hour).

If you prefer warm toasted bread, spread softened butter lightly on one side of each challah slice. Heat a skillet over medium heat and toast buttered sides until golden, about 1–2 minutes per side. Alternatively, toast in a toaster or oven until lightly browned.

Lay out 4 bottom slices of challah. Divide the prepared tuna salad evenly among them (about 3 oz tuna salad per sandwich). Spread into an even layer, leaving a small border so it doesn't spill when closed.

Top the tuna on each sandwich with 1 cup divided baby greens (if using), then arrange thin radish slices evenly across the tuna to add crunch and peppery bite.

Place one provolone slice on top of the radishes for each sandwich. Finish with the remaining challah slices to close the sandwiches.

If you prefer the cheese slightly melted, place assembled sandwiches in a preheated skillet over low heat, cover, and warm 1–2 minutes per side until cheese softens. Otherwise, serve cold or room temperature.

Slice sandwiches in half on the diagonal and serve immediately. Leftover tuna salad can be refrigerated in an airtight container for up to 3 days.