Blend or pound pandan leaves till fine. Mixwith water and squeeze out juice. (If colour is not dark enough,add green colouring.) Mix alkaline water to the pandan juice mixture. Add sugar and salt and bring to a boil until sugar dissolves.
Add hot mixture into glutinous rice flour. Add mashed sweet potato and mix well. Blend in corn oil. Knead into a smooth dough. Divide dough into small portions. Flatten each slightly, add coconut filling.
For moulding and steaming, refer to the steps for making angkoo.
[For the filling: ]Put (B) in a non-stick pan to slowly meltthe sugar until it turns syrupy. Add (A) and lower the heat. Keepstirring till mixture is almost dry. Add (C) and stir well to blend. Cook for five minutes, then transfer to a tray to cool.