Food from old king's rule? (8)
I believe the answer is:
coleslaw
'food' is the definition.
(coleslaw is a kind of food)
'old king's rule?' is the wordplay.
'old king's' becomes 'cole's' (nursery rhyme character Old King Cole).
'rule?' becomes 'law' (rule is a kind of law).
'coles'+'law'='COLESLAW'
'from' is the link.
(Other definitions for coleslaw that I've seen before include "Indeed" , "Shredded vegetable salad" , "Salad dish based on shredded cabbage" , "We locals consume shredded cabbage and carrots with dressing" , "Salad dish of dressed shredded cabbage" .)