One hour before cooking the lag of lamb, rub the meat with the powdered ginger, the pepper, the thyme (4 stripped sprigs) and the 2 bay leaves cut into strips. Wrap it tightly in the muslin, tie it up with string. Place the leg of lamb in a casserole, pour boiling salted water over it and cover. Bring to a boil. Count 15 minutes of cooking per lb for the meat to be rare. Serve with boiled and buttered mixed vegetables, a turnip, celeriac or onion purÄe. Serve the mint jelly (as if mustard) and veloutÄe white sauce with 2 or 3 tablespoons of capers. This fine dish is delicious served cold or hot.