The most important thing to take note of is to soak both the Lentils and the Tamarind in enough for atleast an hour. Alternatively if you wish to quicken the process, you can boil Tamarind for about 3-4 minutes. Let it cool down before you squeeze the juice out. Keep it aside.
Now add rest of the ingredients to a Pressure cooker except those listed under tempering and Tamarind water. Cook for 6-7 whistles or until done. Also add half of the Curry Leaves. Let the steam settle down on it's own before opening the lid of the cooker. After opening, add Tamarind water and let it boil for a few minutes until the raw smell of the Tamarind fades away.
Adjust the consistency accordingly. Though it's semi thick. Neither too thick nor too watery. Adjust Salt too as required. And finally add the tempering. Tempering is a must and the quantity of Oil should be more. Otherwise Khatti Daal won't taste good. Be generous in doing so. But do not add too much of it either. Garnish with finely chopped Coriander Leaves. Serve it hot with your favourite side dishes and relish it's awesome taste and flavour. Enjoy!
