Shell the chestnuts and put them in cold water with a little salt and bring to the boil. Peel then carefully and put in a saucepan with the carrots, cut in half, the potato cut in 2 or 3 pieces, and the seasoning. Add 1 pint of water, and simmer till the chestnuts are quite tender. Then rub the chestnuts, the carrots and the potato through a sieve, put this purée into a saucepan and add a little hot stock to thin the purée. Stir well, simmer for a few minutes, and serve with croûtons of fried bread. A little sugar is sometimes added to this soup.