Wash and soak tamarind in about a cup of water or enough to immerse tamarind in water. Soaking in warm or hot water helps.
Soak for at least one hour. The longer you soak, easier it is to extract the pulp.
With a clean hand, press and squeeze soaked tamarind to extract the pulp.
Transfer tamarind extract to a separate bowl, pour some water to tamarind and extract more pulp.
Transfer the extract to the bowl and repeat the process, if you feel you could extract more pulp from tamarind. Try to keep the extract as thick as possible. I used about 1 - 1½ cups of water.
Transfer tamarind extract/juice to inner pot of the Instant Pot (IP).
Add remaining ingredients, close the IP lid, make sure the vent is sealed.
Cook on Manual / Pressure Cook mode for 11 minutes. Make sure the pressure is on high.
It will take about 10 - 13 minutes for the pressure to build up, depending on the quantity of liquid in the pot. Then it cooks for 11 minutes.
Let the pressure release naturally. This should take about 15 - 20 minutes and then pressure pin will drop indicating natural pressure release.
Press cancel, open the lid, press saute and cook for another 10-15 minutes until pulihora paste consistency is reached. Keep stirring in between and in the last 4-5 minutes, there is going to be a lot of splutter and spillage. You may want to semi cover the pot with a lid.
The other option is to adjust the IP setting to low but this will take longer to thicken the paste.