Clams: To purge clams of sand, soak in cool water with 2 pinches of salt for at least 30 minutes.

Cuttlefish or Squid Preparation The sweet, nutty flavor of these chewy cephalopods is crucial to numerous rice dishes. Either can be used, as the flavor and texture are similar. Generally speaking, a cuttlefish-sepia in Spanish, sipia or sepia in Catalan-resembles a large squid. It is meatier, slightly more tender, and a bit more flavorful than squid, and is ideal for cutting into thin strips. It is sold fresh and also frozen as cuttlefish steaks. Squid-calamar in Spanish and Catalan-is equally excellent. Use the tentacles as well as the body tube, which can be cut into strips or rings. When buying fresh squid or cuttlefish, look for whole ones with their heads intact. They need to have a clear, fresh, sea-briny smell. When cleaning, reserve the ink sacs to use in Arròs negre amb allioli (Black Rice with Allioli, page 78). To clean, pull out the head and entrails. Carefully remove the ink sac(s) found beneath the tentacles, and reserve. Trim off the tentacles and reserve, discarding the rest. Remove the hard, clear quill from inside the tube and any innards that remain. Packets of squid ink can be bought at select stores, including Italian and Asian markets.

To Grate Tomatoes:. Simply cut the tomato in half crosswise, and run a finger through the seed cavity, scraping most of the seeds out. Then, cupping the tomato in your hand, slowly grate on a box grater. The skin will gradually peel back as the flesh is grated away, leaving only a flattened skin in your palm. (Discard the skin.) This technique doesn’t waste precious pulp. In winter when good, flavorful fresh tomatoes are hard to find, canned whole tomatoes can be used. Strain them, reserving the liquid (to add later to the cooking sofrito), and finely chop.

Saffron Threads Preparation: Saffron is a defining element of paella. It brings its characteristic warm and fresh aroma, and, significantly, tints the rice a delicate golden color. It is the world’s most expensive spice. Cultivation is a delicate process, collecting is difficult, and it takes some 70,000 flowers to yield a pound of saffron. Introduced into Spain around A.D. 900 by Arab traders, it was cultivated in Spain by A.D. 960. (The Spanish word for saffron, azafrán, comes from the Arabic za’faran.) Saffron is largely grown in the central La Mancha region, whose extreme conditions-hot summers, cold winters-are ideal for giving strength to the color and pungency to the aroma. La Mancha is a registered denominación de origen; look for the “D.O. Azafrán de la Mancha” label. Buy only threads and not powder, which may have been adulterated.

To draw out saffron’s full culinary potential, the threads need to be slightly toasted and crumbled before they are added to a rice dish. Toast the threads in a small dry skillet over low heat for a few minutes until they turn a shade darker. Remove them immediately, and then either crumble them in a small piece of paper or pound them in a mortar. If using a mortar, be sure to swirl a bit of water around inside after pounding to get every last bit of saffron dust.

Most restaurants, and many home cooks, use a powdered colorante (usually a mix of cornstarch, salt, and yellow dye) to give their paella the dish’s characteristic golden color. Though eschewed by purists, colorante does not carry a heavy stigma in Spain and its use is not generally looked down upon around most tables. Colorante gives the rice an artificially bright yellow tone. Do not try to make a paella yellower by simply adding more saffron. Too much saffron can give the rice a bitter, almost medicinal flavor. Two pinches of good-quality threads-20 to 30 total-is enough for a paella for 6.