Soak the cashew nuts for 4-8 hours (I soak mine overnight) in a bowl of water so that they soften.
Rinse and drain the cashews then place them into a blender with the rest of the ingredients. Pull the probiotics capsule apart, empty the powder into the blender and discard the capsule. Blend until smooth.
Pour the mixture into a clean jar and cover with a piece of cheesecloth or kitchen paper to keep it clean. Leave for up to 24 hours to ferment naturally. Pour into a container with a lid and store in the fridge to stay fresh for up to 5 days.
Notes
To thicken the yogurt lay a folded piece of cheesecloth (or paper coffee filter) in a strainer and sit it over a bowl. Pour the yogurt over the cloth/filter, cover and place in the fridge for 12-24 hours to allow some of the liquid to fall through into the bowl underneath. Check several times over that period until the yogurt reaches your desired consistency. You may notice a little separation which can be quite normal with yogurt. Stir the yogurt so that it comes together again.