Pickled herrings

• 6–8 fresh herrings
• coarse salt
• 1 medium-sized onion
• ½ pint

Clean the herrings and remove the heads and tails. Place on a work surface and spread them out flat, skin side up. Press along the back to loosen the bone, then turn each herring over and gently pull away the bone. Cut each fish in half down the centre to make 2 fillets. In an earthenware or china dish, arrange fillets in layers, sprinkling each layer with salt to cover and finishing with a spr