Sprinkle the steaks with the pepper.
In a large no-stick frying pan over high heat, sear the steaks for about 1 minute per side.
Transfer to a plate and tent with foil to keep warm.
Add the tomatoes, stock and vinegar to the pan and cook for 3 to 5 minutes, or until the liquid is reduced by half.
Return the steaks to the pan and heat through.