Meanwhile, juice two lemons, collecting the juice in a dish. Add 2 tbsp olive oil, the garlic cloves and the spices (thyme, piri piri, cumin, sumac, cinnamon and saffron). Stir and place the lamb cutlets into the dish. Coat them in the marinade, cover the dish and place it in the fridge. Leave to marinate for 1 hour if you have time.