Right oven for Sunday lunch? (5)
I believe the answer is:
roast
'sunday lunch?' is the definition.
(I've seen this before)
'right oven' is the wordplay.
'right' becomes 'r' (common abbreviation).
'oven' becomes 'oast' (oast is a kind of oven).
'r'+'oast'='ROAST'
'for' is the link.
(Other definitions for roast that I've seen before include "Give a telling off to - cook" , "Cook (meat) in oven" , "One way to cook meat" , "open-air party in US" , "Slate" .)