>>64240486
That's the D-ration from WW2. It was the emergency chocolate bar meant for that desperate moment when you have no other food left.

Military specifically requested from the company that made the bars that "It should be about as palatable as a cooked potato" so that the troops would not eat it until they really needed it. It still had the calories of a chocolate, just not the good taste.

Modern MRE's have chocolate that is actually tasty.