Gigot àia provençale

• 1 leg of lamb (about 2.7 kg/6 lb)
• 1 tablespoon

Ask the butcher to trim and tie a leg of lamb. Pre-heat the oven to slow (150°C/300°F/Mark 2). Butter a shallow oven-proof casserole or gratin dish just large enough to hold the leg of lamb comfortably and rub it lightly with a cut clove of garlic. Peel the potatoes, cut them into thic