Have a sufficient quantity of good strong broth as for any other soup, taking care that it is not too strongly flavoured by any of the roots introduced into it. Peel a good quantity of the best turnips, selecting such as are not bitter. Sweat them in butter and a little water till they are quite tender. Rub them through a tamis, mix them with the broth; boil it for about half an hour. Add half a pint of very good cream, and be careful not to have too fierce a fire, as it is apt to burn.