In a saucepan, pour the foie gras marinade and enough chicken broth to cover the cylinder while cooking. Place the thermometer in the saucepan and heat until the thermometer reads 60 °C (140 °F). At that time, add the foie gras. Poach for 25 minutes keeping the liquid at 60 °C (140 °F). Remove the foie gras from the broth and refrigerate for 24 hours.