When it comes to crafting the ultimate fish sandwich, there are multiple factors to consider. Firstly, the fish must be top quality.
“Sand whiting is readily available and flakes beautifully. And slashing the skin prevents the fillet from curling,” shares GT food editor Maxwell Adey. “Crumbing fish holds better than a batter, so it sits well in the sandwich as it creates structure.”
This recipe also pays homage to both British crustless sandwiches and Japanese konbini sandos. “The bread should be soft to contrast with the texture of the crisp crumbed fish,” says Adey. Sauce is also essential. In a nod to fish master Josh Niland, we’ve added yoghurt to the tartare. “This lightens it and adds acidity, as does the addition of pops of finger lime.”
And we’ve gone for two sauces, along with pickled fennel, to balance the stacked style of this fish sandwich. “This adds tang, heat and sweetness.”
A guindilla and cornichon are the savoury cherry on top, with a crunchy side of salted potato chips.
Ingredients
Method
Slash fish skin and halve fillets crossways. Place fish in a large bowl; pour over buttermilk to submerge, then cover and refrigerate to lightly brine (2 hours).

For pickled fennel, combine vinegar, sugar, fennel seeds and ¼ tsp sea salt flakes in a bowl and stir to dissolve the sugar. Add fennel, toss to coat, then set aside, tossing occasionally, until lightly pickled (15 minutes). Drain before serving. For spicy honey mustard, combine all ingredients in a bowl. For tartare, combine all ingredients in a bowl and season to taste.

Drain fish fillets from brine and pat dry with paper towel. Place flour, pepperberries and 2 tsp salt in a shallow dish. Place egg and panko in separate shallow bowls. Dust fish evenly in flour; shaking off excess. Dip into egg and then press into crumbs, coating evenly. Place on a baking tray lined with baking paper; refrigerate until ready to cook.

Heat 1cm oil in a large frying pan over medium-high heat until shimmering. Shallow-fry fish, in batches, turning once, until golden brown and just cooked through (1 minute each side; be careful, hot oil will spit). Drain on a rack set over a baking tray lined with paper towel, then immediately place a piece of cheese on each to melt.

To assemble, place one-third prepared bread slices on a clean work surface, spread with spicy honey mustard and top with lettuce. Place another layer of bread on top, spread with tartare sauce, place fish and pickled fennel on top, then sandwich with remaining bread slices. Top with a cornichon and guindilla to garnish, skewered with a cocktail pick. Serve with potato chips on the side.