For the buah keluak, you need to soak for 3 days, scrub each of them and change the water everyday.
On the 4th day, take them out and break the end with the sharper end of the pestle. Remove the flesh and discard the rotten ones and the bitter ones. Discard also the bitter parts. Chop up the flesh and season with sugar, salt and some pepper.
If you like, mix the flesh with some minced pork.
Meanwhile, boil the shells for 15-30 minutes, and then restuff the shells with the flesh.
Heat the oil in a pot to medium heat.
Add the spice paste, lemon grass and fry at low heat until the oil turns red. It takes about 10 minutes.
Add the chicken pieces stir through. Add the prepared nuts.
Lower the heat to the lowest.
Prepare the tamarind juice by massaging the tamarind into the water and then filter for the water only.
Add the tamarind juice to the chicken and buah keluak.
Simmer until chicken is cooked. I like to use very low heat.
When cooked, switch off and let it rest on the stove for not more than 8 hours. If you need to keep it longer, put it in the fridge.
Serve the dish hot with steamed rice.