The first rule of spaghetti with clams: the sauce has to be white. If you should be served this recipe in its “red” version, covered in tomato sauce, you are authorised to send it back to the kitchen. In fact the delicate flavour of the molluscs does not tolerate other intruders, and adding tomato would simply ruin the composition. If you really do not like the white version, two or three cherry tomatoes tossed in the skillet and lightly salted may be allowed.
Although it may seem an easy dish to make, like all dishes with very few ingredients, there are plenty of traps along the way: every ingredient has to be of excellent quality and cooked with no margin for error. In this particular case, there are just five ingredients: pasta, clams, oil, chili pepper and parsley. Let’s start with the most important one, the clams. One fool-proof trick for recognising them is to look carefully: if their “little horns” are separate, that means they come from the Mediterranean and are the most flavoursome “vongole veraci” (“real” clams), whereas if there is just one horn, then they are Manila clams. If you then want to amaze any cook who makes this dish for you by saying that he actually used “lupine” clams, learn to recognise them. They are a smaller variety, but very tasty, and unlike other species they have no antennae of any kind and are taken mainly from the Adriatic.
Like any other mollusc, clams do not tolerate long cooking times; it would make them rubbery and tasteless: the trick is to turn off the heat and cover the skillet with a lid as soon as the first shells start to open. Purists also insist that you must not add white wine, which, in order to be cooked off, would require a dangerous extension of the cooking time. Sometimes the clams are joined by mussels, but these recommendations on time and cooking are also true for this type of mollusc. Many people customarily leave the clams under running freshwater for at least an hour; this operation is supposed to eliminate sand and impurities, but in fact to achieve this you simply need to run the clam liquid remaining in the bottom of the skillet through a fine mesh or sieve. You can replace this step with a simple rinse.
The real secret of this dish, since you can’t rely on a true sauce, is to achieve the right creaminess to bind together all the ingredients: one trick is to drain the spaghetti well before it reaches the al dente stage and finish cooking in the filtered clam cooking juices. The starch in the pasta will do the rest. Chili flakes are not an optional ingredient but need to be added carefully in very small doses, so as not to cover over the pleasant saltiness of the clam sauce. For a gourmet touch, add a sprinkling of dried mullet roe (bottarga).