By Josceline Dimbleby
Shallots are far sweeter than larger onions. My family love this soup’s mild mustardy flavour.
Melt the butter in a large pan, add the cauliflower and onion and stir over a gentle heat for 10 minutes or until the onion is translucent and the cauliflower is tender. Whizz in a food processor with 300 ml (½ pint