Why This Recipe Works

We dressed up quick-cooking, mild tilapia with heady blackening seasoning for a spicy, satisfying sandwich. Tilapia fillets are notable for composing one whole side of the fish’s body. The belly portion is thicker than the top portion, so we divided the fillets at their natural seam and sautéd them separately for more even cooking. A quick tartar sauce and lots of crisp lettuce provided cooling contrast to the smoky fish.

Before You Begin

Store-bought blackening seasoning (1½ tablespoons) can be used in place of the seasoning mixture.

Instructions

Sprinkle 4 skinless tilapia fillets, halved along natural seam, all over with ½ teaspoon table salt and let sit for 15 minutes. Combine ¾ cup mayonnaise, 2 tablespoons sweet pickle relish, 1 tablespoon minced shallot, and 1½ teaspoons distilled white vinegar in bowl; set aside. Combine 1½ teaspoons paprika, ½ teaspoon pepper, ½ teaspoon dried thyme, ½ teaspoon dried oregano, ½ teaspoon garlic powder, ⅛ teaspoon cayenne pepper, and remaining ¾ teaspoon salt in small bowl.

Place ¼ cup all-purpose flour in shallow dish. Sprinkle fish all over with seasoning mixture, then dredge in flour. Heat 3 tablespoons vegetable oil in 12-inch nonstick skillet over medium-high heat until just smoking. Add thicker fillets to skillet. Cook until golden brown on both sides and registering 130 to 135 degrees, 2 to 3 minutes per side. Transfer to plate. Add thinner fillets to skillet and cook until golden brown, about 1 minute per side. Transfer to plate.

Spread tartar sauce on cut sides of 4 split and toasted sub rolls, then top with fish and 2 cups shredded iceberg lettuce. Serve.