Beef Stew with Black Trumpet Mushrooms

Trim all visible fat from the flank steak. Slice the steak diagonally into very thin pieces, about 1/8-inch thick.

Heat 2/3 of the oil in a saucepan over high heat until it begins to smoke. Add the beef and sear on all sides. Cook until the juices which have been released from the beef evaporate completely.

Remove the beef and immediately add the remaining oil. Add the carrot, onion, and celery. Cook until tender.