Parsnip is sometimes called a forgotten vegetable, but in fact it's really back in fashion. Its mild flavour makes it an ideal vegetable to use in soup and it complements the sourness of the apple and the smoky salmon.
Peel the parsnips and chop coarsely. Finely chop the onion.
Heat the olive oil in a soup pan. Fry the onion for about 3 minutes until translucent and soft. Add the parsnips and fry briefly. Crumble the stock cubes above the vegetables. Add 1 litre of water and bring to the boil. Then reduce the heat and simmer the soup.
In the meanwhile, thinly slice the apple and slice the spring onion into rings.