Lentil Soup

• 40 g (1½ oz) butter
• 1 onion, chopped
• 150

Melt the butter in a large saucepan over medium heat. Add the onion and lentils, and cook, stirring, for 10 minutes, or until the onion is very soft. Next, add the carrot, potato, tomato paste and 1 litre (35 fl oz<