Make Pandan Juice Extract: Begin by washing and cutting the pandan leaves into 1 inch pieces. Cut enough so that you have ½ cup of pandan pieces (approximately 5-10 leaves depending on their size). Place the cut leaves in a small blender with ½ cup of water and blend until the leaves are broken down. Strain to remove the leaves, reserving only the pandan juice. Set aside.
Boil Agar Agar Powder: Combine the agar agar powder with 4 cups of water in a saucepan on the stove. Bring to a gentle boil and allow to cook for approximately 10 minutes, stirring occasionally.
Add the Sugar: Add the sugar to the mixture and stir until dissolved. Turn the heat down to low so that the agar agar mixture remains hot, but is not continuing to boil.
Make Pandan Layer: Remove 2 cups of the agar agar mixture from the pan and place into a separate bowl. Add the pandan juice to this bowl and stir to incorporate. Pour into a shallow pan or mold and allow this pandan-flavored layer to harden. It will harden at room temperature, but if you prefer to speed up the process, you can put it in the refrigerator.
Make Coconut Layer: While the pandan agar is solidifying, add the coconut milk to the remaining agar agar mixture on the stove. Mix to incorporate. Once the pandan layer has solidified, slowly pour the warm coconut agar agar layer on top. Allow this layer to solidify, either at room temperature or in the refrigerator.
Serve: Once both layers have solidified, remove from the mold or pan and cut into desired shapes. You can top this agar agar dessert with fresh young coconut meat for a pretty presentation, if you like.