2. Put the red wine mixture and the lamb in a resealable plastic bag. Turn the bag over several times to be sure that all of the lamb is in contact with the liquid. Refrigerate overnight.
3. Preheat the grill for indirect grilling. Arrange the coals in a circle, leaving the middle empty or light the burners on one side of the grill.
4. Remove the lamb from the bag and discard the leftover liquid. Generously season the lamb with salt and pepper.
5. Place the lamb on the grill away from the direct heat, either in the center of the circle of coals or on the opposite side of the grill. Close the lid. Cook the lamb until a thermometer measures 140°F in the center of the meat or to the desired doneness, about 10 to 15 minutes per side.
6. Remove the lamb from the grill and let it rest on a platter for 10 minutes before slicing.
Serve with spring vegetables such as new potatoes, carrots and peas.