Crispy Fish Sandwich Recipe

In a small bowl combine 1/2 cup mayonnaise, finely minced dill pickle (or 2 tbsp jarred relish), 1 tbsp chopped capers, 1 tsp fresh lemon juice, 1/2 tsp Dijon mustard, 1 tbsp chopped parsley, 1/4 tsp salt and 1/4 tsp black pepper. Stir until smooth. Taste and adjust acid or salt as needed. Refrigerate while you prepare the rest of the sandwich so flavors meld.

Preheat oven to 425°F (220°C) if baking fries. Wash and peel (optional) russet potatoes, then cut into 1/4- to 1/2-inch sticks. Soak cut potatoes in cold water for 10 minutes to remove excess starch; drain and pat dry thoroughly.

Toss dried potato sticks with 1 tbsp olive oil, 1/2 tsp salt, 1/4 tsp black pepper and 1/4 tsp paprika (if using). Arrange in a single layer on a baking sheet lined with parchment. Bake 20–30 minutes, turning once, until golden and crisp. Alternatively, deep-fry in 350°F (175°C) oil for 3–4 minutes until golden, drain on paper towel and season with salt immediately.

Pat the fish fillets dry and cut into portions roughly the width of your buns (4 portions from 1 lb). Season both sides lightly with 3/4 tsp of the salt and 1/4 tsp black pepper.

Set up three stations: a shallow dish with 1/2 cup all-purpose flour mixed with 2 tablespoons of the cornstarch (reserve remaining cornstarch), a bowl for batter, and a plate for finished pieces. Keep batter and sparkling water very cold: place bowl with sparkling water and ice cubes for a moment if desired.

Make the batter: whisk together remaining 1/4 cup corn starch, 1 tsp baking powder and a pinch of salt. Add 3/4 cup cold sparkling water gradually while whisking until a slightly thick but still airy batter forms (adjust with a splash more water if too thick). Batter should coat the back of a spoon but remain light.

Heat vegetable oil in a deep skillet or heavy pot to 350°F (175°C). If you don't have a thermometer, test by dropping a small bit of batter — it should sizzle and puff immediately.

Dredge each seasoned fish piece in the flour mix, shaking off excess, then dip into the batter to fully coat. Carefully lower into hot oil, frying 3–4 minutes per piece (depending on thickness) until batter is golden brown and fish registers 140–145°F (60–63°C) and flakes easily. Fry in batches to avoid crowding; maintain oil temperature between 325–350°F.

Remove fried fish to a wire rack set over a sheet pan or paper towels to drain. Sprinkle very lightly with remaining 3/4 tsp salt while hot.

If desired, lightly butter the cut sides of the buns (2 tsp butter total) and toast in a skillet over medium heat until golden, about 1–2 minutes per side. Keep warm.

Spread about 1 to 1 1/2 tablespoons of the prepared tartar sauce on the bottom half of each bun.

Place a handful (about 1/2 cup) of shredded iceberg lettuce on top of the sauce, then set a hot piece of fried fish on the lettuce.

Top the fish with 2 pickle slices, then a light additional drizzle or dollop (about 1 teaspoon) of tartar sauce on the top bun if desired. Close the sandwich and serve immediately with fries and lemon wedge on the side.