To make pandan juice, cut washed pandan leaves into 1/2" segments. Combine 1/2 cup of these leaves with 1/4 cup of water in a blender and blend until it forms a paste. Strain the paste through a mesh strainer until you have extracted all of the juice. You should have ~1/4 cup pandan juice which will be used later in the recipe.
Combine the water, jasmine extract, sugar, and coconut milk in a saucepan and heat over low heat until the sugar dissolves. Transfer to a bowl and add the tapioca flour and rice flour. Mix well until all lumps are incorporated and the batter is perfectly smooth.
Divide the batter into halves. Leave one half plain. To the other half, add the 1/4 cup pandan juice you made earlier. You'll also need to add 2 tablespoons tapioca flour and 1 tablespoon rice flour to counteract this increased liquid so that the pandan layer sets as well as the plain coconut one does.
Place a 4" x 4" container in a steamer. Spoon 4 tablespoons of the pandan batter into the container and let steam for 10-15 minutes until no liquid remains on top of the layer. Next add 4 tablespoons of the plain coconut batter on top and steam until done. Repeat this process until you have 9 layers (the top and bottom layers should be pandan).
Let the container cool to room temperature and then cut into a square. To get a clean cut, it helps to put the entire container in the fridge to cool for a while.