Fish Sandwich Recipe

In a small bowl, combine mayonnaise, chopped dill pickle or relish, chopped capers (if using), lemon juice, Dijon mustard and chopped parsley. Stir until smooth and well combined. Season with 1/4 tsp salt and a pinch (about 1/8 tsp) black pepper. Taste and adjust acidity or salt. Refrigerate while preparing the fish so flavors meld (at least 10 minutes).

Pat the fish fillets dry with paper towels. If fillets are large, cut into 4 sandwich-sized portions (about 4–5 oz each). Lightly season both sides with a pinch of salt and pepper.

Prepare the batter: In a shallow bowl or wide mixing bowl whisk together 3/4 cup all-purpose flour, 1/4 cup cornstarch, 1/2 tsp baking powder, 1 tsp salt, 1/2 tsp black pepper and 1/2 tsp paprika until homogenous.

Slowly stir in 1/2 cup cold club soda or cold beer to the dry mix until you have a thick, smooth batter. The consistency should coat the back of a spoon but still be slightly runny; add a tablespoon more liquid if too thick. Keep batter cold — set bowl over an ice bath if your kitchen is warm.

Heat 1/2 cup vegetable oil in a large skillet over medium-high heat until shimmering and a drop of batter sizzles immediately (about 350°F/175°C). You want enough oil to shallow-fry and crisp the batter underside; add a little more oil if necessary to maintain temperature.

Dust each fish piece lightly in the remaining 1/4 cup cornstarch (or a tablespoon of extra flour if you prefer) to help the batter stick. Dip each piece into the batter to coat completely, let excess drip off briefly, then carefully place into the hot oil. Fry in batches without crowding — 2 pieces at a time depending on skillet size.

Cook the fillets 3–4 minutes per side, turning once, until the batter is golden-brown and crisp and the fish registers 140–145°F (60–63°C) or flakes easily. Adjust heat to keep oil at an even sizzle — not smoking. Total fry time will vary by thickness.

Transfer cooked fish to a paper towel–lined plate and season immediately with a light pinch of salt. Keep warm in a low oven (200°F / 95°C) while frying remaining pieces.

Prepare vegetables: Slice tomato into 4 even slices and thinly slice 1/4 red onion. Halve the lemon and squeeze 1/2 lemon over the tomato slices lightly to prevent discoloration and add brightness.

Toast the buns: Spread 1/2 tsp butter (or brush oil) on cut sides of each bun. Heat a clean skillet over medium heat and toast buns cut-side down until golden and slightly crisp, about 1–2 minutes.

Assemble each sandwich: Spread about 1.5 tbsp of the tartar-style sauce on the bottom bun. Place 1 leaf of lettuce, then a hot battered fish fillet, top with a tomato slice and a few rings of red onion. Spoon another 1 tbsp sauce on the top bun and close sandwich. If desired, squeeze a few drops of the remaining lemon over the fish before closing.

Serve immediately with optional sides such as fries, coleslaw, or pickles.