Drain the soaked cashews and discard the soaking water. Place the cashews in the cup of a high-speed blender along with the 310g of water. Blend until very smooth then pour out into a large bowl. To the bowl add the sweetened condensed coconut milk. Whisk to combine then set aside.
Combine all the remaining ingredients in a medium bowl and whisk well until all the chocolate and coconut oil has melted and everything is well combined. (nb. the heat from the boiling water should be enough to melt everything but if this doesn’t work, place the bowl over a saucepan of boiling water and stir until everything is melted and combined).
Pour the chocolate “liquor” into the cashew and condensed coconut milk mixture. Blend with an immersion blender until completely combined and smooth. Cover the bowl with cling film or a large plate and place in the fridge to cool for an hour. Do not leave to cool overnight or it will become too solid!
Once cooled, give it another whizz with the immersion blender to homogenise and then pour into an ice cream maker and freeze according to the manufacturer’s instructions. While freezing, select the vessel you’d like to store your ice cream in and place it in the freezer to chill.
Once the blades of the ice cream machine can’t turn any more and the ice cream resembles soft serve, stop the machine. Remove the ice cream and place a few spoonfuls in the bottom of your storage container. Sprinkle over some pieces of cake then top with more ice cream. Repeat until you’re out of ice cream then top with a final layer of cake. Press the cake down lightly into the ice cream.
Freeze the ice cream for at least 2 hours before eating it. If you freeze it overnight it’ll need to defrost slightly before it becomes scoopable, so take it out of the freezer 10 mins before you need it.