Scrub the mussels, knock off any barnacles, and tug off the ‘beards’. Rinse the mussels thoroughly and discard any that fail to close when tapped. Put them in a saucepan, cover tightly and steam over a high heat for 2–3 minutes. Drain the mussels in a colander set over a bowl to collect the cooking juices. Discard any that fail to open. When cool enough to handle, shell the mussels and put them in a bowl of warm water to stop them drying out. Strain the cooking juices into a large saucepan, and add sufficient water to cook the spaghetti. Bring the water to the boil, and add the spaghetti. Bring back to the boil, and boil for 2 minutes. Stir, remove from the heat, and cover the pan with a tight-fitting lid. (See the method.) Leave the spaghetti to continue cooking for the full time stated on the packet. Three minutes before the time is up, add the drained mussels and the watercress. Stir once more, replace the lid and leave for the allotted time. This is just sufficient to wilt the watercress to a soft, bright green and heat the mussels through. The pasta will be perfectly cooked. Drain it and transfer immediately to a heated serving dish. Stir in the olive oil, and grind on some black pepper. A little salt may be needed, but the mussels will probably be briny enough without it.
In July and August, when samphire is in season, I love to cook the small, cleaned sprigs with the spaghetti instead of watercress. The mussels can be replaced with clams.
© 1995 Frances Bissell. All rights reserved.