Filet O Flounder Sandwich Recipe

Prep fillets

Pat flounder fillets dry with paper towels. Season both sides with kosher salt (about 1 tsp total) and black pepper. Drizzle lemon juice and 2 tablespoons olive oil over fillets and let rest 5–10 minutes at room temperature while you prepare coatings and sauce.

Grill method

Preheat a grill or grill pan to medium-high (about 425°F / 220°C). Oil the grates or brush fillets lightly with oil to prevent sticking. Grill fillets skin-side down (if skin-on) for 3–4 minutes, then flip and cook 1–2 minutes more until the fish is opaque and flakes easily. Internal temperature should reach 145°F (63°C). Remove and keep warm.

Pan-sear method

Heat a large nonstick or stainless steel skillet over medium-high heat with 1 tablespoon oil. When shimmering, add fillets and cook 3–4 minutes per side, depending on thickness, until golden and cooked through (fish should flake easily). Transfer to a plate and tent with foil.

Blackened method

Mix 1 tsp Cajun seasoning and 1/2 tsp paprika and pat onto both sides of fillets. Heat a cast-iron skillet over high heat until very hot and add 1 tablespoon oil. Place fillets in skillet and sear 2–3 minutes per side until a dark crust forms and fish is cooked through. Vent area if spices smoke.

Fried/breaded method

Set up a dredging station: flour (or a 50/50 flour and cornmeal mix), beaten egg, and panko breadcrumbs. Dredge each fillet in flour, shake off excess, dip in egg, then press into panko. Heat 1/4 inch neutral oil (vegetable or canola) in a skillet over medium-high to 350°F (175°C). Fry fillets 2–3 minutes per side until golden and cooked through. Drain on paper towels.

In a small bowl combine 1/2 cup mayonnaise, finely chopped dill pickle, 1 tsp chopped capers, 1 tsp lemon juice, 1/2 tsp Dijon mustard, 1 tsp chopped fresh parsley, 1/4 tsp salt and 1/8 tsp black pepper. Mix until uniform. Taste and adjust acidity or seasoning. Chill in refrigerator for at least 10 minutes so flavors meld.

Lightly butter the cut sides of the brioche buns (about 2 tbsp total). Toast buttered sides in a skillet or on the grill over medium heat until golden, about 1–2 minutes.

Spread about 1 to 1.5 tablespoons tartar sauce on the bottom bun. Place a leaf of lettuce on the sauce to act as a moisture barrier, then set a warm flounder fillet on top.

Add 2–3 tomato slices (or enough to cover the fillet) and two dill pickle chips per sandwich. Spoon another 1/2 tablespoon tartar sauce on the top bun if desired, then close the sandwich.

Serve each sandwich immediately with a lemon wedge on the side for squeezing over the fish and additional tartar sauce if desired.