Peel and dice the garlic, roughly chop the gherkins, juice the lime, pick the leaves from the herbs. Add all of these along with the capers, mustard and anchovies to a pestle and mortar or food processor and blend with the olive oil to a rough paste, don't over work it as this will form a puree and not a paste.
Wash and dry the chard. Cut the white end at the bottom of the chard into 1 inch batons and set aside. Cut the rest of the chard into strips. Put a saucepan onto a medium heat, add the oil and cook the chard whites for 3-4 minutes or until soft, then add the tops, season with the salt and pepper and cook for 1-2 minutes.
Heat a large frying pan and when hot add the oil. Season the fish with salt and pepper. Then pan fry the fish skin side down for 3 minutes on a medium heat. When the fish turns golden around the edge flip it over and turn the heat off, allowing the residual heat in the pan to finish the cooking.
Serve with the swiss chard as a base with the fish on top and dressed with salsa verde.
«Try adding a little butter to the pan as you fry the fish and baste it as you cook .»