Bit more than a crust earned?
I believe the answer is:
bread and butter
'earned?' is the definition.
(I've seen this before)
'bit more than a crust' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is located in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for bread and butter that I've seen before include "pudding" , "basically reliable" , "Subsistence" , "Ordinary" , "earned?" .)