1. Trim any excess fat from lamb, sprinkle lamb with pepper. Place lamb on a rack in a baking dish. Bake in moderate oven for about 45 minutes or until lamb is cooked as desired. Serve with the sauce.

2. Pour any pan drippings from lamb into a small frying pan, add onion and bacon, cook, stirring, until bacon is crisp. Add rosemary, port and water, bring tot he boil, reduce heat, simmer uncovered until reduced to ½ cup liquid. Add cream, simmer, stirring, until slightly thickened; strain before serving.