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' says the letters should be written in reverse.
'extravagant' becomes 'OTT' (abbreviation for 'over the top').
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'sir' in reverse letter order 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" .)