Put the coconut milk, sugar, cinnamon and nutmeg into a small saucepan. Scrape the seeds from the vanilla pod into the pan, whisk to combine and then heat very gently for 10 minutes to allow the flavours to combine. Set aside.
Meanwhile, put the butter beans in a blender and blitz until just broken down. Remove the vanilla pod, then pour in the coconut milk and blend until smooth. Using a fine sieve, push the mixture through into a jug.
Pour the mixture into an ice cream-maker and churn according to the machine’s instructions – you want it to be roughly the same consistency as soft-serve ice cream.
Transfer to an airtight container and freeze for at least 4 hours.
To serve, put the raspberries in a small saucepan with the caster sugar and a couple of tablespoons of cold water. Heat gently, breaking down the raspberries with the back of a spoon until you have a sauce-like consistency. Push through a sieve and then into a serving jug, to drizzle over the ice cream. Scatter with the remaining raspberries.