Slow-cooked butterfly lamb leg

Ingredients

• 2 garlic cloves, crushed
• 2 tsp ground cumin
• 2 tsp turmeric
• 1 tsp ground coriander
• 1 tsp cinnamon
• 1 tsp sea salt
• 2 tbsp olive oil
• 1.5 kg lamb leg, boned and butterflied
• 1/3 cup unsweetened yoghurt
• 1/3 cucumber, grated
• Handful mint leaves, shredded
• Juice of 1 lemon
• Splash of olive oil
• Fresh coriander, to serve
• Chilli flakes, to serve
• 1 buttercrunch lettuce, separated into leaves