Food offered by witch wearing blusher? (8)
I believe the answer is:
roughage
'food' is the definition.
(roughage is a kind of food)
'witch wearing blusher?' is the wordplay.
'witch' becomes 'hag' ('hag' can be a synonym of 'witch').
'wearing' means one lot of letters goes inside another.
'blusher?' becomes 'rouge' ('rouge' can be a synonym of 'blusher').
'hag' placed into 'rouge' is 'ROUGHAGE'.
'offered by' is the link.
(Other definitions for roughage that I've seen before include "Essential food" , "something that can make your passing more bearable" , "Indigestible material good for intestines" , "Vegetable fibre" , "Indigestible material to stimulate intenstines" .)