Scottish Oaty Vegetable Soup

1
Add vegetables to olive oil and 'sweat' them over a very gentle heat, with the lid on, for five minutes, until just coated and softened.
2
Stir in the oatmeal and cook for another minute or so, stirring to prevent sticking.
3
Pour in the stock and stir well.
4
bring to the boil, then reduce the heat and simmer, covered, for 45 minutes.
5
Add seasoning (if using) and parsley.
6
Finally, add milk (if using), reheat gently, and serve hot.