Steak Diane with Roasted Sage Potatoes

Heat oven to 450 degrees F. Toss potatoes with 1/2 tablespoon of the oil, sage leaves, and salt in a shallow roasting pan. Roast 22 to 25 minutes, tossing occasionally, until crisp and golden. Meanwhile, boil beef broth in a small saucepan 10 to 12 minutes, until broth is reduced to 1/2 cup. Stir in Dijon mustard; reserve. Trim steaks, removing large pieces of fat and any gristle. Cut each steak in half. Flatten between plastic wrap to an even 1/4-inch thickness. Rub steak with soy sauce and 1/2 tablespoon of the oil. Heat the remaining 1 tablespoon oil in a large nonstick skillet over high heat; add butter, swirling pan to coat. Add 2 pieces of steak; sear 1 minute per side for medium rare. Remove to a platter; loosely cover to keep warm. Repeat with the remaining 2 pieces of steak; add to platter. Add shallot to drippings in skillet and sauté 30 seconds. Pour in reserved broth mixture, parsley, lemon juice, and Worcestershire sauce. Return steaks to skillet just to coat in sauce. Serve immediately with roasted potatoes, spooning sauce over steaks.