Preheat the oven to 425?F.
Heat the oil in a large skillet over high heat until almost smoking. Season the beef on all sides with the salt and pepper and transfer to the skillet. Cook until well browned on all sides, turning with tongs when necessary, 8 to 10 minutes. Transfer the beef to a cutting board or platter and, using a rubber spatula or spoon, rub it all over with Creole mustard and garlic. Cover the meat with the chopped herbs, using your hands to evenly pat them into the mustard coating. Place the prepared filet in a shallow roasting pan and cook until a meat thermometer inserted in the thickest part registers 125?F for medium rare, 20 to 25 minutes. Remove the meat from the oven and let stand for at least 10 minutes before slicing.
Makes 8 to 10 servings
Note: The meat may also be served at room temperature; but don't slice it until just before serving.