Toast 60 g (2¼ oz) brown or white rice (brown produces more flavour) in a dry frying pan until fragrant and starting to brown. Cook according to your usual method until tender. Drain off any water and transfer to a blender with 650 ml (22½ fl oz) cold water. Blitz on high power until smooth and creamy. Push through a fine sieve to remove any stray rice grains and add more water if too thick.