Jewish Deli–Style Tuna Melt With Relish, Dill, Celery, and Swiss Recipe

Ingredients (12)

• One 5-ounce (142g) canned oil- or water-packed tuna, drained well
• 1/2 cup (120g) mayonnaise, such as Hellmann's (see note)
• 2 tablespoons (10g) panko bread crumbs (optional; see note)
• 2 tablespoons (20g) minced red onion
• 1 tablespoon (5g) minced fresh dill
• 1 tablespoon (20g) drained sweet relish
• 1/2 rib celery (30g), very finely diced
• 1/2 teaspoon (5g) coarse ground mustard
• Kosher salt and freshly ground black pepper
• Four 1/2-inch-thick slices rye sandwich bread
• Vegetable oil, clarified butter, and/or melted butter, for brushing the bread
• 4 slices Swiss cheese