First, to ensure that the meat is at room temperature. The out of the fridge at least one hour before preparation. Heat a large skillet over medium high heat.
When the pan is hot, place the steaks and cook a few minutes on each side ( 3 to 4 for rare steak and 6 to 7 for well done steaks). Reserve covered on aluminum foil.
Add the port and stock in the pan to deglaze the meat juices (Deglaze is just to make a gravy or sauce by adding liquid to the cooking juices and food particles in a pan in which meat has been cooked). Reduce heat to medium. Add a tablespoon of butter. Let reduce until the sauce thickens.
Meanwhile, heat another large skillet over high heat without adding any fat. When the pan is hot, cook the slices of foie gras about 15 seconds on each side. Place the foie gras slices over paper towels.
Arrange the plates, add a spoonful of sauce Porto first, then season the steaks with sea salt and pepper and place them on the sauce; Place a slice of foie gras on each tournedos and season with a little sea salt and pepper.
Optionally, you can place the steaks on a slice of toasted bread and finally, add black truffle slices on each slice of foie gras.