Wiktionary
iron ration
n. (context historical English) An emergency ration given to soldiers in the early 20th century, consisting of cakes made from beef bouillon powder and wheat; chocolate; and packets of salt and pepper.
Usage examples of "iron ration".
He rummaged through the cabin and dug out an iron ration which he shared with Satchel and Jimmie.
They sat on either side of it in the gathering twilight, Edge heating over the flames a pan of sagamite, the cavalryman's iron ration of mixed cornmeal and brown sugar.
If he had suspected that he would never go back there, he could have brought them along as an iron ration.