Peach yogurt occasionally, following roast (8)
I believe the answer is:
knockout
'peach' is the definition.
(I know that peach can be written as knockout)
'yogurt occasionally following roast' is the wordplay.
'occasionally' indicates alternate letters (letters taken at regular intervals or occasions).
'following' means one lot of letters go next to another.
'roast' becomes 'knock' (synonyms).
The alternating letters of 'yogurt' are 'out'.
'out' after 'knock' is 'KNOCKOUT'.
(Other definitions for knockout that I've seen before include "stunner" , "triumph" , "Boxing blow" , "Stunning blow" , "The quietus in boxing" .)