Curried Sweet Potato and Lentil Soup

Serves 4 45O g (1 lb) sweet potatoes, peeled and diced 1 onion, chopped finely 1 garlic clove, crushed 1 tablespoon medium curry powder 85O ml (1 1/2 pints) vegetable stock 50 g (1 3/4 oz) dried split red lentils salt and freshly ground black pepper 2 tablespoons chopped fresh coriander, to garnish Place the sweet potatoes, onion, garlic, curry powder, stock and lentils in a large saucepan and bring to the boil. Reduce the heat, cover and simmer gently for 30 minutes, stirring from time to time. Transfer the soup to a food processor or liquidiser in batches, and blend until smooth. Return the soup to a clean saucepan and heat through. Season to taste, ladle the soup into four warmed bowls and garnish with fresh coriander