Eggs containing key salad ingredient (7)
I believe the answer is:
romaine
'salad ingredient' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'eggs containing key' is the wordplay.
'eggs' becomes 'roe' (I've seen this before).
'containing' is an insertion indicator.
'key' becomes 'main' (I've seen this in other clues**).
'roe' placed around 'main' is 'ROMAINE'.
Can you help me to learn more?
(Other definitions for romaine that I've seen before include "Type of lettuce - I arm one (anag)" , "Cos lettuce" , "Variety of lettuce" , "lettuce in America" , "lettuce in the US" .)