Combine the oats, coconut milk, water salt and cinnamon in a small saucepan and bring to the boil.
Allow to simmer for 5 minutes then add the apple, cranberries and walnuts.
Remove the saucepan from the heat then cover and allow to steam for 10 minutes.
After 10 minutes, stir in the butter and sweetener (if using) and serve.
(I topped mine with a few cubes of apple and a few cranberries and walnuts but this is optional.)