I would make a furnace and place it down. I would then add coal to the furnace as well as raw iron in their designated spots. The iron would not smelt, but sit in the furnace as an uncookable item. I would then swap the iron for raw meat and the meat would cook. I then put the iron back into the furnace after the meat has cooked and the raw iron again would not smelt. The raw iron is supposed to smelt in the furnace and the cooking arrow is supposed to fill up per item cooking. the arrow would not fill up.