Cola nut roasting, cooked and well done (15)
I believe the answer is:
congratulations
'well done' is the definition.
(I've seen this before)
'cola nut roasting cooked' is the wordplay.
'cooked' indicates an anagram.
'cola'+'nut'+'roasting'='colanutroasting'
'colanutroasting' with letters rearranged gives 'CONGRATULATIONS'.
'and' is the link.
(Other definitions for congratulations that I've seen before include "good show" , "praise" , "Cliff Richard hit" , "well done" , "Best wishes" .)