To obtain pandan juice, chop the pandan leaves and blend them in an electric blender with 250ml water.
Use a muslin cloth to squeeze out the juice then mix with the green colouring and alkaline water.
Pour the pandan juice into a saucepan and bring to a boil.
Blend green bean flour with the extra cup of water into a smooth batter and add to the boiling pandan juice, stirring all the time until the mixture is transparent and thick. Remove immediately from the heat.
Place a cendol frame over a basin half-filled with ice-cold water. Put a little cooked mixture on the frame. Press the cooked mixture through the frame to form little droplets of cendol.
Leave the cendol to set in the ice water till firm. Add more ice cubes to the water to set the cendol faster. Drain in a colander and refrigerate till ready to use.
To prepare the palm sugar syrup, boil palm sugar, sugar, water and screwpine leaves until both sugars have dissolved completely. Strain and allow to cool completely.
For the coconut milk, add water to grated coconut. Squeeze in small handfuls using a muslin cloth. Add salt to the coconut milk.
To serve, spoon the desired amount of cendol into serving bowls, add some crushed ice and pour on some coconut milk and one tablespoon palm sugar syrup or to taste.