Bringing back memories about slight smell? (11)
I believe the answer is:
reminiscent
'bringing back memories' is the definition.
(reminiscent means recalling a particular thing)
'about slight smell?' is the wordplay.
I cannot quite see how this works, but
'about' could be 're' ('re' means regarding or about) and 're' is present in the answer.
'slight' could be 'mini' (slight can mean small or mini) and 'mini' is found in the answer.
'smell?' could be 'scent' (scent is a kind of smell) and 'scent' is found within the answer.
No letters remain.
This explanation may well be incorrect...
(Other definitions for reminiscent that I've seen before include "Redolent" , "Suggestive of the past" , "Like Proust, perhaps" , "Stirring memories" , "Recalling" .)