Method

• 1.
  For the brine, place all ingredients in a heavy-based saucepan with 3L water and bring to the boil over high heat. Remove from heat and strain through a fine-meshed sieve, discarding solids. Store in the fridge. Do not use until completely cooled.
• 2.
  Place lamb in a large non-reactive container, pour over enough brine to cover, then cover with plastic wrap and refrigerate overnight.
• 3.
  Remove lamb from container and pat dry with paper towel. Discard brine.
• 4.
  Preheat oven to 130°C/110°C fan-forced.
• 5.
  Place lamb in a casserole with the garlic, rosemary and stock. Cover and roast for 4 hours, or until meat is falling off the bone. Remove from the oven, transfer to a baking tray and stand, uncovered.
• 6.
  Increase oven to 200°C/180°C fan-forced.
• 7.
  For the roasted beetroot, place 2 x cross-sections of doubled sheets of foil on a work surface. Arrange large beetroot on top of one, and baby beetroot on the other. Season with salt flakes and freshly ground black pepper and bring foil edges together. Pour over white wine vinegar, then secure edges together to make a bag. Roast baby beetroot for 1 hour and large beetroot for 1 hour 25-1 hour 30 minutes until tender, then remove from oven and set aside to cool. Using rubber gloves if desired to avoid staining your hands, peel beetroot. Cut large beetroot into thick wedges and halve baby beetroot.
• 8.
  Switch oven to grill function and set to high heat. Return lamb to oven and grill, uncovered, for 5-8 minutes until golden brown and crisp.
• 9.
  Meanwhile, for the mint salsa, whiz herbs, oil and garlic in a food processor until smooth. Transfer to a bowl, stir in vinegar and season with salt flakes and freshly ground black pepper.
• 10.
  Place lamb on a serving plate. Toss beetroot through olive oil and balsamic vinegar and arrange around the lamb. Spoon mint salsa over the lamb shoulder and serve.