Garnish: pomegranate seeds and freshly chopped coriander
Preheat the oven to 200°C (400°F). Rub the lamb with 2 tbsp olive oil and 2 tsp fleur de sel. Transfer to a baking dish and roast for 30 minutes or until golden.
Sprinkle with za’atar, pour in the stock and cover. Reduce the oven to 160°C (325°F) and roast the lamb for 2½ hours.
Mix all the ingredients in a bowl, cover and chill until needed for the tahini yoghurt. If you prefer the sauce a little thinner, dilute with a bit of water.
Once the lamb is cooked, sprinkle with more za’atar and serve drizzled with tahini yoghurt (diluted with a bit of water) and sprinkled with pomegranate seeds and chopped coriander.