Freshly made hot flan gets an enthusiastic response (3,4)
I believe the answer is:
not half
'an enthusiastic response' is the definition.
(expression used to indicate agreement)
'freshly made hot flan' is the wordplay.
'freshly made' indicates an anagram.
'hot'+'flan'='hotflan'
'hotflan' is an anagram of 'NOT HALF'.
'gets' acts as a link.
(Other definitions for not half that I've seen before include "Absolutely (but less than 50%!)" , "Extremely" , "Very much, exceedingly" , "like a bigger drink?" , "I agree 100%" .)