A bread roll and crackers before time - that's ample (8)
I believe the answer is:
abundant
'ample' is the definition.
(I've seen this before)
'a bread roll and crackers before time' is the wordplay.
'bread roll' becomes 'bun' (I've seen this before).
'crackers' indicates anagramming the letters (informal term for mad).
'before' is a charade indicator (letters next to each other).
'time' becomes 't'.
'and' with letters rearranged gives 'dan'.
'a'+'bun'+'dan'+'t'='ABUNDANT'
'that's' acts as a link.
(Other definitions for abundant that I've seen before include "Plentiful, profuse" , "In plentiful supply" , "Copious, profuse" , "Luxuriant" , "Present in large quantities" .)