1. In a large glass, ceramic, or stainless steel bowl, whisk together garlic, rosemary, oil, vinegar, salt, and pepper. Place lamb in marinade, turning to coat thoroughly. Marinate 2 to 24 hours.

2. To roast in oven: Preheat oven to 425 degrees F. Drain marinade from lamb and discard marinade. Place lamb in a 9- by 12-inch roasting pan. Roast in oven until medium-rare (about 45 minutes, or until internal temperature is 135 degrees F on an instant-read thermometer). Let lamb rest 15 minutes before serving. Carve across grain into 1/2-inch-thick slices. To grill: Prepare a charcoal fire; brush grill rack with vegetable oil. Drain marinade from lamb and reserve. Place lamb on rack and grill 10 minutes, baste with marinade, turn and grill 10 minutes, baste again, and turn and cook 10 minutes more. Repeat until internal temperature is 135 degrees F(about 15 minutes more). Rest and carve lamb as for roasting.

Mediterranean Lamb Chops: Marinate 4 lamb sirloin steaks (about 3/4 pound each) in one half of the marinade; saute steaks in 4 tablespoons olive oil, 3 minutes on each side.

also delicious grilled. Leftover lamb can be made into sandwiches or used in salads (see Lamb and White Bean Salad, in this cookbook).