first of all, prepare your dal. wash your toor dal in running water and transfer it into a pressure cooker. add water and pressure cook it for 3-4 whistles. mash the dal and keep it aside.
meanwhile, chop your veggies and keep aside.
heat oil in a pan and add mustard and cumin seeds.
add curry leaves.
add onion and green chili. saute them for a while.
add chopped vegetables.
also, add tamarind.
add water and mix well.
cook the veggies until soften and cooked on medium flame.
once the veggies are cooked add tomatoes,sambar masala, red chili powder, and some coriander powder.