To make the filling:
Cut the palm sugar into chunks and place in pot with water and knotted pandan leaves. Bring to a boil then lower heat and add the grated coconut, mixing well. Keep stirring so the coconut doesn't burn and cook until almost dry and the coconut is moist. Transfer to a bowl and let cool.
For the batter:
Roughly chop the pandan leaves and put in blender with water and liquify. Strain with cheesecloth to get the pandan juice.
Put the flour and salt into a mixing bowl. Pour in the egg, and slowly whisk in the coconut milk and pandan juice. Make sure the batter is not lumpy and add in a little more water if it's too thick.
Heat a little butter in a non-stick pan and ladle some batter to make a thin pancake. Cook and then flip the other side until it's done.
Place the pancake onto a plate and add a spoonful of filling down the center. Fold the right side over the filling, then fold both top and bottom in and roll the pancake from right to left.