Eight-Hour Lamb Shoulder with Couscous and Labne

Ingredients

• 150 gm Greek yoghurt
• 1 cup (loosely packed) coarsely chopped coriander
• 2 tbsp each coriander and cumin seeds, and sumac, plus extra sumac to serve
• 6 garlic cloves
• 2 lemons, rind finely grated, lemons thinly sliced
• 2 tbsp olive oil
• 1 lamb shoulder (about 1.8kg)
• Pearl couscous
• 2 onions, thinly sliced
• 3 garlic cloves, thinly sliced
• ½ tbsp cumin seeds, coarsely crushed
• 300 gm pearl couscous
• 550 ml chicken stock
• 80 gm barberries or currants
• 1 cup each (loosely packed) coarsely torn mint and parsley