Step 1

Dry-roast peppercorns and cumin until fragrant (1-2 minutes). Cool slightly, then pound in a mortar and pestle. Add garlic and coarsely crush, then add salt and stir to combine.

Step 2

Place lamb shoulder in a roasting pan to fit snugly. Rub salt mixture over, cover with plastic wrap and refrigerate to marinate (4 hours-overnight).

Step 3

Preheat oven to 150C. Add 250ml water to pan, cover tightly with foil, then roast until lamb is tender (2 hours). Reduce oven to 110C and cook until very tender and falling off the bone (add a little more water if pan becomes dry), removing foil for the last hour of cooking to crisp the skin (6 hours).

Step 4

Meanwhile, for fried garlic, heat oil to 170C in a saucepan over medium heat, add garlic and stir occasionally until light golden (30 seconds-1 minute). Drain on absorbent paper.

Step 5

For lemon sauce, pound preserved lemon in a mortar and pestle to a smooth paste, add vinegar, whisk to combine, then slowly add olive oil and whisk to combine.

Step 6

For cumin salt, dry-roast cumin until fragrant (1-2 minutes). Cool slightly, then pound in a mortar and pestle until coarsely ground. Add salt and pound to just combine.

Step 7

Skim fat from pan juices (discard fat) and transfer pan juices to a jug. Place lamb on a serving platter and shred meat from bone at the table. Serve warm scattered with fried garlic, cumin salt and chilli, with pan juices to the side.