Wash the lentils and cook in pressure cooker by adding 2 cups of water.
When done remove from the cooker and blend the cooked lentils using a hand blender till it is smooth and keep aside.
Cook the vegetables in a deep bottomed pan with one cup of water on a medium flame till the vegetables are soft. Remove from the pan and keep aside.
Heat oil in the same pan, add mustard seeds, curry leaves and asafetida and sauté for few seconds.
Add the tomatoes, mix well and cook on a medium flame for 2 minutes, while stirring occasionally.
Add the cooked vegetables, cooked dal, tamarind pulp, turmeric powder, onions, salt and ¾ cup of water and cook on a medium flame for 5 minutes.
Add coriander, mix well and cook on a medium flame for 2 minutes.
Serve hot with steamed rice or breakfast items like idly, dosa or vada.