French Onion Soup

A good onion soup is a classic recipe to have in your repertoire; ideal for autumn evenings and cold winter lunches, and knocked together with the simplest and cheapest of ingredients. I use this recipe as a baseline and often substitute half of the stock for ale or white or red wine, as the mood takes me. You can use any kind of onions here; be they red, white, green or spring, any onions will do.