The day before you want to make ice cream, place the freezer bowl of your ice cream maker into the freezer to freeze properly.
Then add your coconut milk, coconut cream, sugar, syrup and cocoa powder to a pot and heat to a simmer. You'll need to whisk it with a hand whisk to mix the cooca powder in properly, but thereafter you can just stir gently until it reaches a simmer.
Remove from the heat and whisk in the vanilla.
Break the dark chocolate into pieces and add, leaving for a minute to give it a chance to melt, then whisk in until smooth.
Then blend in the pot with an immersion blender for 30 seconds to remove any last trace of graininess from your mixture. If you don't have an immersion blender, then transfer to your blender jug and blend.
Transfer the mix to a sealable container and place into the fridge to chill completely. It may thicken into a chocolate mousse consistency, this is fine.
Transfer to your ice cream machine and churn until it reaches soft serve consistency. If it's quite thick going in, then this may only take around 20 minutes, but churn it for as long as possible (at least 20 minutes) so that it incorporates enough air to be light and fluffy.
Smooth down into a loaf pan, cover with foil and place into the freezer to set completely before serving.
Serve topped with chopped dark chocolate (optional).