Maybe not what soldiers want for breakfast? (4-6,3)
I believe the answer is:
hard-boiled egg
'breakfast?' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Perhaps there's an association between them I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for hard-boiled egg that I've seen before include "Cooked item provided by 1 down" , "Potential picnic fare" , "Possible picnic item" .)