A little flat-leaf parsley, finely chopped, to garnish (optional)
Remove any prominent bones from the fish fillets using tweezers. Season the flour with salt and pepper on a large plate and press the fillets into the mix to coat on either side. Shake off any excess and set aside on a clean plate.
Heat the oil in a frying pan, which is big enough to accommodate the fish fillets over a high heat. Add the fish fillets, skin-side down, and cook for 2 minutes and then turn over and cook for a further minute until golden. Using a fish slice, remove the fillets from the pan and set aside on a warmed plate.
Place the pan back over a high heat and melt the butter until it is foaming, then add the lemon juice and capers and continue to cook until the butter turns a nutty golden brown.
Pour the butter, lemon and caper mix over the fish and serve straight away garnished with the parsley, if using.