Cover 85 g (3 oz) dried soya beans in 600 ml (21 fl oz) boiling water. Leave to soak for 12 hours, changing the water (cold water is fine) at least once. Drain, rinse and transfer to a blender. Add 500 ml (17 fl oz/2 cups) cold water and blitz until smooth. Strain through a piece of muslin, a nut bag or a clean piece of cut-off tights and squeeze out the milk. Blitz again until completely smooth. Transfer to a pan and gently simmer for 20 minutes, stirring occasionally. Add 1 teaspoon vanilla extract and 1 teaspoon caster (superfine) sugar and leave to cool.