Allow the foie gras to come to room temperature for 1 hour.
Make a shallow incision in the centre of the foie gras and open it gently. Devein it (gently remove the blood vessels) using tweezers or the tip of a knife. Place the foie gras in a dish. Season with salt and pepper on both sides. Drizzle with the port wine. Cover with plastic wrap and refrigerate for 12 hours.
Cut a piece of cardboard the same size as the terrine dish. Wrap it in aluminum foil (this cardboard will be used when the terrine is placed to cool).
Remove the foie gras from the refrigerator and let stand for 30 minutes at room temperature.
With the rack in the middle position, preheat the oven to 100 °C (200 °F).
Place the foie gras in a 15 x 9-cm (6 x 3 ½-inch) terrine dish and cover with aluminum foil. Place the terrine in a water bath. Add enough hot water to fill the bath halfway up the terrine. Bake for about 1 hour and 20 minutes or until a meat thermometer inserted in the centre of the dish reads 55 °C (130 °F).
Remove the terrine from the water bath. Remove the paper and tip the dish very carefully (foie gras is very fragile) to drain any excess fat in a small bowl. Keep the collected fat in the refrigerator and use for sautéing potatoes, wild mushrooms, or pan frying a steak.
Place the aluminum foil-covered cardboard on the foie gras. Press and hold in place with two small cans. Refrigerate for 24 hours.
Unmould by dipping the base of the dish in boiling water. Turn over and slice. The foie gras will keep, well wrapped, for several days in the refrigerator.
Serve with bread buns, fleur de sel and Sauternes or ice cider jelly.
Soak the gelatin in 60 ml (1/4 cup) of cold ice cider or Sauternes for 2 minutes. In a small saucepan, heat the remaining alcohol and then add the bloomed gelatin. Stir to melt and pour into a 20-cm (8-inch) square pan. Let set in the refrigerator for about 2 hours. With a knife, cut small cubes of jelly from the pan. Loosen with a spatula. Arrange around the slices of foie gras.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.