1. Score steak crisscross-fashion on both sides. Place in a cold non-stick skillet over moderate heat. Brown on both sides.
2. Sprinkle each side with 1 teaspoon flour. Turn several times until flour is completely moistened in pan juices.
3. Add onions, lemon juice, wine, poultry seasoning and parsley. Cook, turning frequently until pink inside. Remove steak to a warm serving platter. Sprinkle with salt and pepper. Continue simmering sauce until it thickens.
4. To serve, slice steak diagonally and cover with sauce.