Jerusalem artichokes are native to the USA where they are known as sunchoke or sunroot. They have no connection to Jerusalem: it's thought that Italian immigrants to the US could have referred to them as 'girasole' (sunflower), which was corrupted to Jerusalem. Nor are they an artichoke, but in fact a member of the sunflower family.
Season: November to February These vegetables with a distinctive flavour are a rather neglected delicacy. Although they are cheap and could not be easier to grow, they are largely ignored. My guess is that this is because of their ugliness.
I love serving this, one of my most favourite soups. First, it has an extremely rich, beautiful colour, almost saffron I would say. And second, people can never quite guess what it is.