Heat the oil and cumin seeds. Once the oil is heated, add the potatoes and saute them. Take them out and leave aside. Remove the cumin seeds from the oil and add another 3 tbsp of oil. Add the onions and braise them. Add the bay leaves, cardamom and nutmeg.
Continue frying until the onions turn dark brown. Add the spice paste and after 2 min. pour in 2 tbsp water. Throw in the ginger and garlic and braise another 30 seconds. Add in the lamb meat, cinnamon stick and cloves and saute for 5-7 min.
Add the tomatoes and continue cooking until the liquid is absorbed. Pour in 3 1/2 cups water and salt, put the lid on and cook on low heat for 35 min. Then add the potatoes and cook another 8-10 min. Discard the cinnamon stick and bay leaves and serve.