firstly, in a large vessel add tomatoes, ginger, chili, coriander and curry leaves.
also add turmeric and water.
boil for 10 minutes or till tomatoes turn soft and mushy.
further, mash the tomatoes well with back of the spatula.
now add pressure cooked toor dal. make sure to pressure cook for 5 whistles or till dal is cooked completely.
additionally, add salt to taste.
mix well and adjust consistency by adding water as required.
boil for 3 minutes. do not over boil after adding dal, as it leads to gastric problem.
meanwhile, prepare the tempering by heating up ghee / clarified butter.
once the ghee is hot, add mustard seeds, cumin, red chili, curry leaves, asafoetida and pepper.
once the tempering splutter, pour the tempering onto prepared rasam.
finally, serve lemon rasam / kat saaru with steamed rice.