Pressure cook the tur dal with enough water.
Also cook the tomatoes in the cooker without water.
We can cook the tamarind with little water or in an open vessel with enough water.
Mash the cooked dal well with a potato masher or with your hands itself and keep aside.
Mash the tamarind and extract the juice from it.
Also mash the tomatoes well.
In a pan, add ghee and splutter mustard seeds. Once they crack, add cumin seeds and saute until it turns golden brown.
Add the mashed tomatoes and tamarind extract.
Into this add turmeric powder, jaggery, salt, rasam powder, cumin seed powder, dried coriander powder, asafoetida and curry leaves so that the flavour goes well into the rasam.
Allow it to cook well.
You can add one more cup of water to adjust the consistency and allow it to cook but donot add too much water.
You will start enjoying the aroma of the rasam at this stage.
Once they boil and the foam is formed, add the mashed toor dhal, cook for few min and switch off the stove.
Garnish it with fresh coriander leaves.