European Parliament talks at length about right vegetables (8,7)
I believe the answer is:
brussels sprouts
'vegetables' is the definition.
(brussels sprout is a kind of vegetable)
'european parliament talks at length about right' is the wordplay.
'european parliament' becomes 'brussels'.
'talks at length' becomes 'spouts'.
'about' is an insertion indicator.
'right' becomes 'r' (common abbreviation).
'spouts' enclosing 'r' is 'sprouts'.
'brussels'+'sprouts'='BRUSSELS SPROUTS'
(Other definitions for brussels sprouts that I've seen before include "greens" , "part of the traditional 27 [DINNER] - with 8a" , "Vegetables" .)