Mahi Reuben Sandwich Recipe

Prepare fish

Pat mahi-mahi fillets dry with paper towels and cut into 4 sandwich-sized portions (about 4 oz each).

Season

Season both sides of the mahi portions with kosher salt, black pepper and smoked paprika, pressing seasonings gently so they adhere.

Cook

Heat a large skillet over medium-high heat and add 1 tablespoon olive oil. When oil shimmers, add the mahi portions and sear 3–4 minutes per side (depending on thickness) until an internal temperature of 145°F (63°C) or opaque and flaky. Remove to a plate and let rest 2 minutes, then flake or slice into thick strips for the sandwich.

Make dressing and toss

In a medium bowl whisk together Dijon mustard, apple cider vinegar, mayonnaise, sugar, celery seed, salt and black pepper. Add the thinly sliced green and red cabbage and shredded carrot. Toss thoroughly until cabbage is evenly coated. Adjust seasoning to taste. Let sit 10 minutes to soften slightly while you finish the fish — this keeps a crisp, slightly tangy Reuben-style slaw.

Blend peppers

Chop the roasted red peppers roughly and pulse in a small food processor or finely mince by hand until a coarse chop remains (not completely puréed).

Combine sauce

In a bowl combine the chopped roasted red peppers, mayonnaise, minced dill pickle, chopped capers, lemon juice, minced garlic and minced fresh dill. Stir until uniform. Season with salt and black pepper to taste. Refrigerate until ready to assemble; flavors meld best after 15–30 minutes.

Toast bread

Butter one side of each bread slice lightly. Heat a clean skillet or griddle over medium heat. Place buttered-side down and toast two slices at a time until golden (about 1–2 minutes). Flip if you prefer both sides crisped; otherwise keep one side toasted. Repeat for remaining slices.

Assemble sandwiches

Spread about 1 tablespoon of the roasted red pepper tartar sauce on the untoasted side of each bottom slice of bread (use more if you like). Place a slice of Swiss cheese on two bottom slices, then divide the flaked mahi evenly (about 4 oz per sandwich). Top the mahi with a generous 3/4 to 1/1 cup of the cabbage slaw per sandwich. If you want extra Reuben character, add 1 tablespoon Russian-style dressing on top of the slaw. Cap with the top slice of bread, toasted side out.

Finish on skillet

Return assembled sandwiches to the skillet over medium heat (butter the exterior of the top slice lightly if you want a crisp golden crust). Press gently with a spatula or weight and cook 1–2 minutes per side until cheese is melted and bread is golden. Transfer to a cutting board and let rest 1 minute, then cut in half.

Serve

Serve immediately with extra roasted red pepper tartar sauce on the side and lemon wedges. Enjoy while warm so the cheese is melty and the slaw remains crisp.