burrito staple (4)
I believe the answer is:
rice
'burrito staple' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rice that I've seen before include "Type of grain" , "Asian staple food" , "Paddy field crop" , "Cultivated food grass" , "... his librettist - cereal" .)