Heat the oil in a pan and fry the cinnamon, bay leaves, cloves, cardamom and peppercorns for a minute. Add the onion and fry until golden. Add the ginger-garlic, green chili, lamb and a tsp of salt and stir-fry over low heat for 20-25 minutes. Sprinkle little water if it is too dry. Add turmeric powder, red chili powder, coriander powder, garam masala & 2 tablespoons of water and stir-fry for 5 more minutes. Then add the puréed tomatoes and cook for another 5 minutes. Stir constantly. Now add 4 cups of water and lower the heat. Add the whisked yoghurt. Cook until the lamb is tender and fully cooked. Garnish with chopped coriander leaves. Serve hot.