With its delicate flesh, Dover sole is a much sought-after sea creature with a flavour that belies its odd appearance. Dee McQuillan discovers some unusual facts about this fish.

Dover sole is the most delectable of the flatfish, which is quite surprising once you know that it spends most of its life buried shallowly in the sand gazing up at its prey, which consists of sea worms, tiny bivalve molluscs and other minutiae of the sea bed. Its gaze, of course, is another weird thing. Like all flatfish it begins life as a regular little fry, with eyes on either side of its spine, and ends up as an adult with both eyes on one side and its mouth rather askew.

A slip sole, correctly, is a small Dover sole in the region of 10 oz (275 g) or less, like the ones called for in Delia's Gratin of Dover Sole with Broccoli, Leek and Gruyère Sauce recipe. With small sole you do need to be careful – inferior species get passed off as Dover junior, though once you have become accustomed to the distinctly rounded, squidgy, eyes-right face like a glum glove puppet, you will recognise Dover sole anywhere. The shape is a smoothly elongated oval (no sticky-out fins) and the tail disproportionately small. An entire adult fish can weigh over a pound and, for prime examples of big fish, there is a great demand at top people's canteens such as The Savoy Hotel and Wiltons. So when it comes to Dover sole, the eyes have it!

The fish connoisseur and particularly elegant writer Alan Davidson makes great play with sinistral and dextral flatfish (eyes left and eyes right, in other words), but I have a problem following him, as surely this depends on which way you consider your Dover sole – head or tail first? Either way, both the reading of Alan Davidson (whose titles include North Atlantic Seafood, Seafood of South-East Asia and Mediterranean Seafood, all, sadly, out of print) and the eating of a fine piece of Dover sole are nourishment for the brain.

One further odd thing about this sole is that, unlike any other fish except skate, it is said to improve with a little age – just a day or two. Complicated reasons are given for this ability to mature out of water and some say, quite cynically considering its flavour, that this was the reason why Dover sole became the favourite fish of restaurateurs – in London it has only recently begun to be rivalled for price and popularity by sea bass. The name Dover sole is said to come from this port being the key supplier to London. I have eaten Dover sole fresh out of the water – lucky old me – and thought the flavour was just the best, but the firm, meaty texture of that flesh came as a bit of a shock and it did not lift off the bones easily.

Dover sole range all around our southern waters and the North Sea. Summer warmth brings them near to the shore, but in the winter they are further out, often in the deeps of the North Sea, including the area known as the Silver Pits, which, fish authorities speculate, may have been named after the wealth of Dover sole sometimes found there.