Place the tamarind, jaggery and dates in a 2L pressure cooker.
or just enough to cover the contents.
Close the lid with the weight and cook on high flame. That is the flame should just about cover the bottom of the pan. Make sure it does not reach the sides since it would cause burning of the handles.
Cook for 2 whistles , around 6 minutes.
Switch off the heat and let the pressure settle down.
This is how it looks upon opening.
Add rest of the ingredients along with 1-1/2 cups water and blend to a smooth puree. You can either use a hand blender or transfer to a food processor. Do a taste test and adjust the seasoning to your preference.