Cook the meats, except for the Morteau sausage, in a large volume of water with the bouquet garni and the leek for about 1 hour 30 minutes. Add the sausage after 1 hour of cooking.
Peel and cut the carrots into large dice. Simmer the lentils with the carrots, onion and bay leaves for 30 minutes.
Drain, melt the duck fat, add the lentil mixture, season