Cut the tomatoes in half then toss into the mortar and crush with pestle along with the dried prawns, lime slice, peanuts and snake beans.
Add the green papaya and bruise – do not over work.
Season with palm sugar, lime juice, tamarind water, fish sauce and chilli powder – initially only use about 2/3s of each. Adding more as needed to hone and finish the seasoning.
It should taste sweet and sour, hot then salty.
Tamarind water method:
Soak equal parts tamarind paste into warm water. Allow to soak 10 minutes.
Using your fingers, mash the tamarind well into the water until it feels completely soft.
Next, strain the tamarind water into a fresh bowl and squeeze out as much extract from the pulp as possible. The tamarind water is now ready for use in curries and many other things that require a tangy or sour flavour.