Choose a good leg of lamb with a thin layer of fat. With the point of a sharp knife or skewer, make deep holes all over the lamb, about 2.5cm apart. It is a good idea not to do this on the underside of the joint, in case somebody insists on eating their lamb unflavoured. Divide the rosemary sprigs into tufts of three or four leaves together.
Peel the garlic cloves and cut them into little spikes about the same size as a matchstick broken into three. Stick a spike of garlic into each hole with a tuft of rosemary. Cover and refrigerate for up to 24 hours if you have time.
Heat the oven to 200°C/400°F/Gas 6. Sprinkle the joint with salt and freshly ground pepper and put it into a roasting tin in the oven. Reduce the heat to 180°C/350°F/Gas 4 after 20 minutes. Cook for about 1 hour more for rare lamb, 1½ hours if it is to be well done. Remove the joint to a serving dish and allow it to rest while you make the gravy.
Spoon the fat off the roasting tin. Pour stock into the cooking juices remaining in the tin. Boil for a few minutes, stirring and scraping the pan well, to dissolve the caramelized meat juices (I find a small whisk ideal for this). Thicken with a very little roux and add a little redcurrant jelly if you like. Taste and add salt and freshly ground pepper if necessary. Strain and serve the gravy separately in a gravy boat.
Serve with roast potatoes.
© 2001 Darina Allen. All rights reserved.