Pour all the ingredients into a bowl – reserving a few blueberries for decoration – and mix well.
Decant the oats into two short glasses or two small jars, cover with clingfilm and leave in the fridge overnight.
In the morning, remove the film, give the oats a stir (if you feel they need a little more milk, you can add it now), top with a dollop of yoghurt and more blueberries.