Cereal mix (6)
I believe the answer is:
muesli
'cereal mix' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for muesli that I've seen before include "Swiss cereal" , "Mixture of crushed grain, nuts etc" , "Rolled oats, nuts and fruit mixture" , "Mule is fed with breakfast compound" , "Cereal made with oats and nuts" .)