How to Make It
Heat the oil in a large skillet over medium-high heat.
Season the steak with ½ teaspoon salt and ¼ teaspoon pepper. Cook, 4 to 5 minutes per side for medium-rare. Let rest for 5 minutes before slicing.
Split the baguette quarters and form sandwiches with the steak, Brie, arugula, and red onion.