When cooking by extraction, the item and the medium in which it will be cooked are started cold. This enabled the natural juices to be extracted into the cooking liquid.Simmering and poaching are simply boiling at a lower temperature. These methods are prefered to boiling as boiling would destroy or damage delicate connective tissue of the meat, and toughen the foodstuff. They are used to tenderize tough meat, mainly second and third categories of meat (see first post on cooking methods Concentration vs Extraction).
The most famous receipe using that technic is probably "Blanquette de veau". In that receipe, the liquid used is a white veal stock (chicken stock can also be used) covering the veal cubes by 2.5 cms. The preparation should simmer but never boil for 45 to 60 mn.
Another receipe using poaching method is the famous "Poule au pot".
