Gentleman served up German dish (7)
I believe the answer is:
risotto
'dish' is the definition.
(risotto is a kind of dish)
'gentleman served up german' is the wordplay.
'gentleman' becomes 'sir' (I've seen this before).
'served up' is a reversal indicator.
'german' becomes 'otto' (I've seen this before).
'sir' in reverse letter order is 'ris'.
'ris'+'otto'='RISOTTO'
(Other definitions for risotto that I've seen before include "Perhaps Italian" , "food dish" , "Main course" , "Italian course" , "Italian dish of rice, meat and vegetables" .)