Flatten the chicken: Slice each breast in half horizontally but not all the way through. Open like a book. Sandwich between two sheets of cling film and bash with a rolling pin until evenly flattened to about 1cm thick.
Set up the coating: Crack the eggs into a shallow bowl with the soy sauce and beat with a fork. Put the flour in a second bowl. Mix the panko with the dill in a third bowl. Season the chicken with pepper.
Coat the schnitzels: Dip each piece into the flour, then the egg, then the panko. Press firmly. For extra security, roll the coated chicken between two sheets of parchment paper with a rolling pin to lock the crumbs in.
Heat the oil: Pour a 2cm depth of vegetable oil into a large non-stick frying pan over a medium-high heat.
Fry: Add the schnitzels and cook for 2 to 3 minutes on each side until deep golden. Work in batches so the pan isn't crowded. Drain on kitchen paper.
Make the sauce: Mix the mustard and crème fraîche together, stir in the gherkin batons and dill. Loosen with a dash of pickling liquid if needed.
Serve: Plate with a generous spoonful of gherkin crème fraîche, lemon wedges and a green salad.
