A good soup of Jerusalem artichokes is a very fine thing indeed, its elusively starchy, aristocratic flavour something to be richly savoured. Some folk like to make the soup using milk, or a lot of cream and stock, but here is a much leaner, simpler version, from Brigid Allen's rather splendid Soup Book. Do take Mrs Allen's advice and make sure the artichokes you buy are firm and unwrinkled: if they are tired and squishy, they are the very devil to peel.
2 onions, peeled and chopped
2 carrots, peeled and chopped
2 tablespoons olive oil
700g/1 1/2 lbs Jerusalem artichokes
Just over 1.2 litres/2 pints water
6 black or green peppercorns
For this simplest of artichoke soups, soften the onions and carrots for 10 minutes in two tablespoons olive oil in a heavy, covered pan. Peel and wash the artichokes, cutting each one into several pieces, and add them to the onions and carrots, stirring them in well. Continue softening for five to 10 minutes, then add the water, sea salt and six black or green peppercorns. Bring to the boil, simmer for 30 minutes, and liquidise. Artichokes need a surprising amount of cooking and underdone ones can ruin a soup, so it is better to overdo rather than economise on the cooking time.