To prepare the filling: Bring water and sago to a boil in a saucepan. Add the pandan leaves. Cook for five minutes until sago turns transparent. (Stir every now and then when the sago is cooking to prevent the sago from sticking to the bottom of the saucepan.) Turn off the heat and close saucepan with a lid and leave aside for five minutes.
Pour sago into a wire mash strainer and put through running tap water to wash off the starch. Drain well and put in a small bowl. Add 1 tbsp gula melaka syrup and stir well to mix. Leave aside.
To prepare gula melaka syrup: Combine brown sugar, gula melaka, pandan leaves and water in a saucepan. Bring to a boil; when both sugars have dissolved, strain and leave aside for use later.
To prepare angku skin: Cook sago in 1 1/2 cups water until it turns transparent. Wash sago through running tap water. Drain well and put aside.
Combine agar-agar powder, instant jelly powder, salt, pati santan and gula melaka syrup in a deep saucepan. Cook over medium low heat until it comes to almost a boil.
Add in hoen kwe flour mixture; keep stirring until small bubbles appear. Add cooked sago and stir well to blend. Remove from heat.
Chill the plastic angku moulds well in ice-cold water or the freezer compartment of your refrigerator.
Pour jelly mixture into moulds to two-thirds full. Spoon one teaspoon of sago filling into the centre. Top up with more agar-agar mixture until the mould is full. Leave aside for five minutes.
Place them in the freezer to set for 15 to 20 minutes.
Remove jelly from the moulds and keep jelly in the refrigerator to chill well before serving.