Cook together 600 g (1 lb 5 oz) lentils, 1 litre (1¾ pt or 4½ U.S. cups) water, 125 g (4½ oz) salt belly of pork cut into dice and blanched, a Bouquet garni, 1 onion stuck with a clove and 1 carrot cut in pieces. When tender, drain the lentils and remove the carrot, onion and Bouquet garni. Pound the lentils and pork, pass through a sieve and replace in the cooking liquor. Mix together and pass through a fine strainer. Adjust the consistency with 2½ dl (9 fl oz or 1⅛ U.S. cups) White Bouillon and finish at the last moment with 150 g (5 oz) butter and Pluches of chervil.