Pressure-cook the vegetables with some water until tender. Set aside.
Add garlic, turmeric powder, coriander powder, red chili powder and salt to the beaten yoghurt and grind them into a fine paste. Place the lamb pieces in a bowl and pour this yoghurt mixture over it. Let it marinate for about 2-3 hrs.
Heat the oil in a pan and fry the bay leaves for few seconds and add the ginger and green chilies and fry for a minute. Then add onions and fry until brown. Add poppy seeds and fry for couple of minutes. Put in the tomatoes, and pressure-cooked vegetables and fry for further 5 minutes. Now add the marinated lamb with the yoghurt mixture and 1/2 a cup of water. Cook over low heat until the lamb is tender. Stir occasionally. Add garam masala and mix well. Cook for 10 more minutes. Serve garnished with chopped coriander leaves.