Method

• 1.
  Preheat the oven to 220°C.
• 2.
  Place garlic in a large, heavy-based casserole with a tight-fitting lid. Season lamb and place on top of garlic. Roast, uncovered, for 15 minutes, then turn lamb and roast for a further 10 minutes or until browned.
• 3.
  Meanwhile, place buttermilk in a saucepan over medium-high heat and bring to the boil (the buttermilk will separate). Add thyme and bay leaves, then pour buttermilk mixture over lamb. Cover.
• 4.
  Reduce oven to 140°C. Return lamb to oven and roast, basting every 45 minutes with cooking liquid, for 4 hours or until meat is very tender.
• 5.
  To prepare potato, 30 minutes into the lamb cooking time, place 1 potato, cut-side down, on a chopping board and insert a metal skewer lengthways one-third of the way up from the base (this will prevent you cutting completely through the potato). Thinly slice down through the potato at 3mm intervals until the knife hits the skewer. Repeat with remaining potato.
• 6.
  One hour into the lamb cooking time, add potato to casserole. The potato will become tender in the remaining cooking time, but not golden.
• 7.
  Meanwhile, for the roast pears, place pears in an ovenproof frypan. Brush with oil, then add verjuice, vanilla pods and seeds, bay leaf and thyme. Sprinkle with sugar and 1/2 tsp salt flakes. Set aside.
• 8.
  After 4 hours of cooking has elapsed, remove casserole lid and increase oven to 220°C. Baste potato with cooking liquid and spoon buttermilk curds onto lamb to caramelise. Return lamb to oven, uncovered. At the same time, place pears on the lowest shelf of the oven. Roast for 30 minutes or until the buttermilk curds and pears are golden.
• 9.
  Set pears aside, loosely covered with foil, to keep warm. Transfer lamb to a large tray and set aside, loosely covered with foil, to rest.
• 10.
  Transfer three-quarters of the cooking liquid to a saucepan and place, covered, over a low heat to keep warm. Return potato and remaining cooking liquid to the oven and roast for 30 minutes or until potato is golden.
• 11.
  Using two forks, coarsely shred lamb. Serve with potato and pears, drizzled with cooking liquid and sprinkled with extra thyme.