Trim fat from steak and cut into serving pieces. Pound flour into both sides of steak. Heat fat in skillet; brown steak on both sides, season with salt and pepper. Place in Pyrex dish; cover with onion slices. In the same skillet, heat tomatoes, loosening brown bits from the bottom of the skillet. Add Worcestershire sauce and season to taste with salt and pepper. Pour over steak, cover with lid or foil and bake at 350 for 2-2-1/2 hours, till fork tender.
Serve over rice, buttered noodles or mashed potatoes.
