Place the can of coconut milk in the fridge overnight.
Cut the avocados in half, remove the pit and spoon out the avocado flesh.
Put the avocado flesh in a food processor together with the lemon juice and blend until it's a perfectly smooth avocado cream.
Open the coconut milk can upside down (so that the hard cream is on top).
Spoon out the coconut cream until you hit the coconut water (save the coconut water for a different recipe or for a smoothie).
Whip the coconut cream in a bowl with a stand mixer or other electrical mixer until it's a nice, soft coconut whipped cream. Add in the avocado cream and the rice syrup and mix until incorporated.
Put the ice cream in a freezer-safe dish.
Place it in the freezer for at least 4 hours.
If it is too hard to spoon out after 4 hours, let it sit at room temperature for a minute or two. Enjoy!