Fillet of Lamb with Grilled Polenta

• salt and pepper
• 1 pair best ends of lamb, chined and the eye of the meat removed
• a little groundnut oil

To make the sauce, place the browned, chopped lamb bones in a wide, shallow pan, add the vegetables and saute in a little oil until the vegetables are browned. Add the sugar and balsamic vinegar and cook until the vegetables are caramelized. Add the red wine and cook until nearly evaporated, then add enough water to cover the bones. Bring to the boil, turn down to a simmer and skim. Cook for 1½