Place the coconut milk, coconut water, palm sugar, salt and pandan leaf (if using) into a pot and bring to a boil. If not using pandan leaf, you can cook just until the sugar is dissolved without having to bring it to a boil.
Allow the mixture to cool to room temp, then put it in the fridge until completely chilled, preferably overnight. Also place the container you will use to store the ice cream in the freezer, preferably something shallow and wide for faster freezing.
Churn the ice cream in your machine, following the manufacturer’s instructions. Transfer the ice cream into the pre-chilled container and freeze for at least another 2 hours to firm up before serving.
Wash the sticky rice 4-5 times until the water runs clear, then soak for at least 3 hours and up to overnight.
Preheat the steamer over high heat and bring the water to a boil. Drain the rice and steam using using any one of the soak-and-steam methods here. (I don't recommend using the no-soak methods however as they tend to produce softer sticky rice which can get mushy when soaked in the syrup)
While the rice steams, make the coconut syrup by combining the coconut milk, sugar and salt in a small pot and bring to a simmer, stirring to dissolve the sugar. Remove from heat and cover while you wait for the rice.
Place the cooked rice in a heatproof mixing bowl and pour the coconut syrup over; stir to mix well making sure there are no rice clumps. Cover and let rest for 20 minutes, then come back to give it a stir, folding the bottom up to the top, and let sit for another 20 minutes before serving.
To store extra sticky rice, separate the rice into 1-portion sized clumps and freeze them. When you want to use them, take out the number of clumps you want, cover in a moist paper towel and microwave for about 30 seconds or until steaming hot and soft. Allow to cool to room temp or lukewarm before putting ice cream on it!
You can serve the ice cream in a bowl by placing a little sticky rice in the bottom and then top this with the ice cream and toppings. To serve in a bun, place the sticky rice in the bottom of the bun and top with the ice cream and toppings. Enjoy!
