Sandwiches etc weren't beefy enough for Spooner (6,5)
I believe the answer is:
packed lunch
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for packed lunch that I've seen before include "Cold meal (eg, taken to school)" , "Meal to be carried" , "Ready-prepared midday meal in container" , "Food carried on a day trip" .)