Add fatty stuff to heart of cabbage, say (6)
I believe the answer is:
butter
'add fatty stuff' is the definition.
I can't judge whether this defines the answer.
'heart of cabbage say' is the wordplay.
'heart of' means to look at the middle letters.
'say' becomes 'utter' (to utter something is to say or speak it).
The middle of 'cabbage' is 'b'.
'b'+'utter'='BUTTER'
'to' is the link.
Can you help me to learn more?
(Other definitions for butter that I've seen before include "Milk product" , "goat?" , "Spread derived from cream" , "Dairy product" , "Type of toffee" .)