Toss the beef with 1/2 teaspoon each salt and pepper. Heat the oil in a pressure cooker over medium-high heat. Add the beef and cook, stirring occasionally, until browned on all sides, about 4 minutes. Add the onions and cook, stirring frequently, until the onions soften and begin to brown, about 4 minutes. Add the white wine, mustard and flour, bring to a simmer and cook until reduced by half, about 2 minutes. Add the beef broth, mushrooms, carrots and celery.