With which Sarah had a piece of bread? (5)
I believe the answer is:
salad
'a piece of bread?' is the definition.
I can't tell whether this definition defines the answer.
'with which sarah had' is the wordplay.
'with' means one lot of letters goes inside another.
'which' becomes 'a' (I can't explain this - if you can you should believe this answer much more).
'sarah' becomes 'Sal' (Sally is a common pet form of Sarah).
'had' becomes 'd' (in contractions e.g. 'I'd', 'you'd' etc).
'sal'+'d'='sald'
'a' put inside 'sald' is 'SALAD'.
Can you help me to learn more?
(Other definitions for salad that I've seen before include "Cold dish of various vegetables," , "Cold dish of vegetables or fruits" , "Green, potato, Russian or Waldorf?" , "Raw, green, veg" , "Raw greens, mainly" .)