Sweet potatoes are, as their name suggests, sweet, but they are also deliciously nutty. They make a smooth and wonderful soup. Be sure to buy the orange-fleshed kind; scrape the skin of the sweet potatoes in the shop with your nail — if the flesh underneath is a pale peach colour, they are the ones you want. If, however, they have white flesh it will go a rather unappetizing grey colour when cooked. This sustaining soup, accompanied by crusty bread, makes a lovely light lunch or supper.
Peel the sweet potatoes and chop them up roughly. Put them into a saucepan with the stock, bring to the boil, then cover and simmer for 20-30 minutes until the potatoes are very soft.
Meanwhile, wash and trim the leeks and cut across in roughly 2.5cm/1 in pieces. Cut the bases and tough stalks off the fennel bulbs and remove any scarred outer layers. Reserve any green leaves for garnish. Slice the fennel in half and then cut across in thin slices. Peel the garlic and slice across thinly.
Melt the butter in a large, deep frying pan over a medium heat and add the sliced leeks and fennel. Cook, stirring around fairly often, for about 8 minutes. Then add the sliced garlic and the caraway seeds and cook for 5 more minutes or until both leeks and fennel are soft and slightly browned.
When the sweet potatoes are soft, put them into a food processor, using a slotted spoon and making sure you leave no bits of potato in the stock. Pour
© 1997 Josceline Dimbleby. All rights reserved.