Stir something for breakfast (8)
I believe the answer is:
porridge
I believe this clue is a double definition.
'stir' is the first definition.
(both can mean prison time)
'something for breakfast' is the second definition.
(breakfast food)
(Other definitions for porridge that I've seen before include "milk and oats together" , "Breakfast dish or slangy prison term" , "Hot breakfast food" , "Boiled oatmeal or prison sentence" , "Stir" .)