Crusts, extremely hard, start to soften with olive oil spread (11)

'crusts' is the definition.
Although both the answer and definition are plural nouns, I cannot see how one could define the other.

'extremely hard start to soften with olive oil spread' is the wordplay.
'extremely' means to remove the middle letters (only the extremes of the word are used).
'start to' says to take the initial letters.
'with' is a charade indicator (letters next to each other).
'spread' is an anagram indicator.
'hard' with its middle removed is 'hd'.
The first letter of 'soften' is 's'.
'hd'+'s'+'olive'+'oil'='hdsoliveoil'
'hdsoliveoil' is an anagram of 'LIVELIHOODS'.

Can you help me to learn more?