Rinse pearl sago a few times until water is clear.
Drain the sago through a sieve.
In a pot of boiling water, add pearl sago. Continue boiling for another 10 minutes on moderate flame, stirring constantly to prevent sago from sticking to the pot. Turn off the flame. Cover the pot and leave to stand for 8 minutes. Sago should be fully cooked and transparent.
Drain cooked sago through a sieve. Rinse sago with the sieve under the tap. Drain off all the water.
Spoon sago into small containers and chill in fridge.
If santan is too thick (after chilling), you may add some water to dilute it.