Crispy Fish Sandwich Recipe

In a small bowl combine mayonnaise, dill pickle relish (or chopped pickles), chopped capers (if using), lemon juice, Dijon mustard and chopped parsley. Season with 1/4 teaspoon salt and 1/4 teaspoon black pepper. Stir until smooth and refrigerate while you prepare the rest of the sandwich to let flavors meld.

Cut and season

Pat fish fillets dry with paper towels and cut into portions roughly the size of the buns (about 4 pieces). Lightly season both sides with 1 teaspoon salt and 1/2 teaspoon black pepper (use the salt and pepper listed in battered fish ingredients).

Set up dredge and batter

Place 1/2 cup all-purpose flour on a plate and mix with 1/4 teaspoon paprika and 1/8 teaspoon garlic powder (from the batter ingredients). In a medium bowl whisk together 1/4 cup cornstarch, 1/4 cup all-purpose flour, 1/2 teaspoon baking powder, 1 large beaten egg and 1 cup ice-cold sparkling water (or cold beer). Whisk until just combined; small lumps are okay. Keep batter chilled—place bowl over another bowl filled with ice if your kitchen is warm.

Heat oil

Pour about 2 cups vegetable oil into a deep skillet or medium saucepan to reach roughly 1 to 1 1/2 inches deep. Heat over medium-high until oil reaches 350°F (175°C). If you don't have a thermometer, test by dropping a small dollop of batter—if it sizzles and browns in about 45–60 seconds, it's ready.

Dredge and fry

Lightly dredge each seasoned fish piece in the flour mixture, shaking off excess. Hold the fish by one end and dip into the cold batter, allowing excess to drip back into the bowl. Carefully lower the battered fish into the hot oil (do not overcrowd; fry in batches). Fry for 3–4 minutes per side, turning once, until the coating is deep golden-brown and the fish registers 140–145°F (60–63°C) or flakes easily. Remove with a slotted spatula to a wire rack set over a baking sheet; keep warm in a 200°F (95°C) oven while finishing remaining pieces.

Optional crisp finish

For an extra-crisp crust, after the first fry, rest the fish for 2–3 minutes, then return to oil at 375°F (190°C) for 30–45 seconds to finish. Drain again on the rack.

While fish fries, spread softened butter on cut sides of 4 buns. Toast buttered sides in a skillet over medium heat until golden and set aside.

On each bottom bun smear about 1 tablespoon (approx.) tartar sauce. Place 1 leaf of lettuce, a slice of tomato (season lightly with salt), then a piece of crispy fish. Top fish with a spoonful (about 1–2 tablespoons) of tartar sauce and a few pickle slices. Add optional slaw or extra lettuce if using, plus a few drops of hot sauce if you like heat. Cap with toasted top bun.

Serve immediately with fries, potato chips or a simple salad.