Ban duke? Squabble about some rehashed stuff (6,3,6)
I believe the answer is:
bubble and squeak
'some rehashed stuff' is the definition.
(dish often made from leftovers)
'ban duke? squabble about' is the wordplay.
'about' indicates anagramming the letters.
'ban'+'duke'+'squabble'='bandukesquabble'
'bandukesquabble' anagrammed gives 'BUBBLE-AND-SQUEAK'.
(Other definitions for bubble and squeak that I've seen before include "breakfast?" , "course" , "Dish of leftovers" , "food" .)