chop all the beans to 1 inch long pieces and keep aside.
wash and pressure cook toor dal with required water till they are completely cooked and soft.
take 1 cup of water and add all chopped beans along with curry leaves.
add a tsp of turmeric powder and mix well. close the lid and allow to cook for 5 min. don't overcook the beans too.
meanwhile, roast cumin seeds, urad dal, coriander seeds and red chillies with a tbsp of coconut oil till you get a nice aroma.
allow it to cool completely. and in a blender take roasted masala, coconut, few curry leaves and tamarind.
blend it to a smooth paste adding required amount of water.
once the beans are cooked add jaggery and salt. bring this to a boil.
now add cooked smashed dal.
also add the ground masala and cook for 10 minutes on a medium flame.
make sure the coconut gets well cooked and the aroma of the sambar rises.
serve hot with steamed rice.