Porridge cousin (6)
I believe the answer is:
muesli
'porridge cousin' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for muesli that I've seen before include "Breakfast cereal mix" , "Breakfast food of cereals, dried fruit, nuts etc" , "Mixture of crushed grain, nuts etc" , "Breakfast dish of cereal, nuts and fruit (6)" , "Breakfast food of cereal, fruits and nuts" .)