Into a clean pressure cooker vessel add the washed tur dal and the water and cook for 3-5 whistles or pulpy.
Release steam naturally, mash the cooked dal and set aside
Peel and dice the pineapple to get 1 cup of pineapple. Divide in half and add one to blend the spice mix.
Collect the rest of the ingredients, wash and clean them.
Dice the tomatoes (half cup) and chop the coriander leaves. Set aside till needed.
Into a deep pan add the oil for tempering along with the mustard seeds and let them crackle.
Then add the curry leaves, asafoetida, and saute till curry leaves are aromatic
Add half cup pineapple and fourth of a cup of tomatoes and saute.
Meanwhile, grind the mix for a smooth paste as given above.
Add the paste of pineapple and tomatoes with the spices to the sauteed tomatoes and pineapple
Now add the spice mix and salt.
Add the two cups of water, mix well and let them simmer for 5 minutes with a closed lid.
Add the half cup of cooked tur dal and mix well. Add the coriander leaves too.
Simmer again for another 5 minutes
The rasam is now ready to serve