Leek and potato soup

It's turning quite autumnal, so what better than a big hot bowl of soup?

Olive oil
Leeks
Onion
Garlic
Potatoes
Mustard
Mixed herbs
Vegetable stock

1.  Slice and thoroughly wash leeks, sautee in olive oil with chopped onion and crushed garlic.
2.  Peel and chop potatoes into small dice, add to the leeks.
3.  Stir in a spoonful of mild mustard and add a sprinkle of herbs, salt and pepper.
4.  Add stock and simmer.
5.  After 10-15 minutes, test the potatoes - when soft  zizzz
6.  Serve, scoff