Small flat dish: slip in fruit (4-1-5)
I believe the answer is:
pied-a-terre
'small flat' is the definition.
(French term for a small flat)
'dish slip in fruit' is the wordplay.
'dish' becomes 'pie' (I've seen this before).
'slip' becomes 'err' (to err is to make an error).
'in' means one lot of letters goes inside another.
'fruit' becomes 'date' (date is a kind of fruit).
'err' placed into 'date' is 'daterre'.
'pie'+'daterre'='PIED-A-TERRE'
(Other definitions for pied-a-terre that I've seen before include "Small home kept for occasional use" , "bijou accommodation" , "Lodging kept for occasional use (French)" , "Small secondary flat or house" , "Dwelling for occasional use" .)