Gentleman returning extravagant duck dish (7)
I believe the answer is:
risotto
'dish' is the definition.
(risotto is a kind of dish)
'gentleman returning extravagant duck' is the wordplay.
'gentleman' becomes 'sir' (a man may be addressed as sir).
'returning' is a reversal indicator.
'extravagant' becomes 'OTT' (abbreviation for 'over the top').
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'sir' back-to-front is 'ris'.
'ris'+'ott'+'o'='RISOTTO'
(Other definitions for risotto that I've seen before include "Italian course" , "Savoury rice dish" , "Perhaps Italian" , "scoff" , "food dish" .)