Place your cashews in a heatproof bowl and cover them in boiling water. Set aside for at least 10 minutes (you can leave them longer if it works for your schedule).
Drain the cashews and place them in a high-speed food processor (I used a NutriBullet). Add 275-300g water and blend until completely smooth and frothy.
Add the caster sugar to a medium saucepan. If you are using the xanthan gum, whisk it into the caster sugar.
Pour the cashew milk into the saucepan and immediately use a silicon spatula to stir thoroughly (if you are using xanthan gum it has a tendency to clump up in the corners of the pot, hence the need for speed).
Weigh in the glucose syrup and add the remaining ingredients, then place on a low medium heat. Cook just until the sugars have completely dissolved, then pour into the 470ml Ninja Creami tub. Because the milk with have frothed up during blending, it’s ok if the mixture is just a tiny bit over the fill line.
Place the tub in the freezer for 24 hours with the lid off. When ready to eat, process the mixture using the ice cream function. You can respin it if needed.
Return any leftovers to the freezer with the lid on. I recommend re-spinning leftovers before eating to restore the texture.