INGREDIENTS
1 small red onion, thinly sliced into rounds
4 oz. bread-and-butter pickles, plus ½ cup brine
¾ cup mayonnaise
1/3 cup chopped dill
2 tsp. hot sauce
1 tsp. freshly ground black pepper
2 tsp. fresh lemon juice, plus wedges for serving
1 tbsp. kosher salt, divided
2 large eggs, lightly beaten
1½ cups panko breadcrumbs
½ cup all-purpose flour
2 flounder fillets cut in half crosswise on a diagonal
2/3 cup vegetable oil
3 cups shredded iceberg lettuce
8 slices sandwich bread
1 cup potato chips, plus more for serving
DIRECTIONS
Combine onion, pickles, and pickle brine in a small bowl.
Mix mayonnaise, dill, hot sauce, pepper, 2 tsp. lemon juice, and ½ tsp. salt in another small bowl.
Place eggs, panko and flour in 3 separate shallow medium bowls.
Season each fish fillet with ½ tsp. salt. Working one at a time, dredge fish in flour, shaking off excess. Coat evenly with egg, allowing excess to drip back into bowl. Coat with panko, pressing to adhere. Transfer fish to a plate.
Heat oil in a large skillet over medium. Cook fish until breading is golden brown and cooked through, 2–3 minutes per side. Transfer fish to a paper towel-lined plate. Season fillets with ½ teaspoon salt.
Spread one heaping tablespoon mayonnaise mixture on one side of each slice of bread. Pile each bottom slice with ¾ cup lettuce, 1 fish fillet, a small handful of potato chips, and ¼ cup onion mixture.
Close sandwich with second slice of bread, mayo side down, and push down lightly to crush potato chips. Transfer to a platter.
Repeat with remaining sandwiches.
Serve with lemon wedges and more potato chips along side.
Do Ahead: Pickled onions and dill sauce can be made 1 day ahead. Cover and chill.
