This is a great dish I made near my family’s historical stomping ground on the Essex coast: Leigh-on-Sea. I used Dover sole, but any sustainable or MSC-approved flatfish like plaice, dab or lemon sole would also be fantastic. Dover sole can be a bit on the pricey side, but they are so tasty that they are a wonderful treat every now and then. You want them skinned, with the heads left on, so ask your fishmonger to do this for you. I've used fresh cockles and peeled brown shrimps, which are deliciously sweet, but way underrated. This dish is best made for two so you can cook everything together quickly in one large pan. There's something about the way these ingredients work together that makes it such a luxurious dinner. Hope you love it..
Sort through the cockles or clams and tap them. If any stay open, throw them away. Give them a wash and slush about in a bowl of cold water. Put a large frying pan on a medium heat and slice the bacon into matchsticks, then add to the pan along with a drizzle of olive oil and fry until lightly golden. Strip the leaves from the sprigs of rosemary and add to the pan. Fry for a few more minutes, then remove everything to a plate with a slotted spoon. Add a small knob of butter to the bacon fat, give it a little shake and carefully lay both fish in the hot pan, head to tail. You're going to cook them at a medium high heat, so it won't take long, but the cooking shouldn't run away from you. Cook the fish for about 4 minutes, then carefully and confidently turn each one over with a large fish slice. Quickly return the rosemary and bacon to the pan and add the shrimps and the cockles or clams. Using a tea towel to protect your hands, cover the pan immediately with a lid or tinfoil, making it as airtight as you can. Cook for another 4 minutes, or until the cockles have all opened.
Finely slice the chives, then remove the foil when the time is up. Squeeze in the juice of a lemon, scatter over the chives, add a good pinch of salt and pepper, then chivvy the pan around with a sense of urgency and remove the fish to a warm platter or two plates, pouring over all the juices and seafood from the pan. Nice served with wedges of lemon on the side and a simple pea and spinach salad, some buttered asparagus or new potatoes.
OK, here's a quick pep talk for you: every house needs an extra-large non-stick frying pan, so if you don't have one, go and get one, otherwise you won't be able to cook two fish at the same time. You will also need a large fish slice. Cooking flatfish like this is very simple, but you mustn’t overcook it. How do you know when it’s cooked perfectly? Simple: gently try to pull the meat away from the thickest part next to the head. If it moves, it's cooked. If it doesn't, it's not