Veggie food content of uneaten sandwiches (4)
I believe the answer is:
tofu
'veggie food' is the definition.
'tofu' can be an answer for 'food' (tofu is a kind of food). I'm not sure about the 'veggie' bit.
'content of uneaten sandwiches' is the wordplay.
'sandwiches' says the answer is hidden in the clue (the answer is sandwiched in by the clue).
'TOFU' is hidden in the letters of 'content of uneaten'.
Can you help me to learn more?
(Other definitions for tofu that I've seen before include "nosh for vegetarians" , "Curdled soybean dish" , "Form of curd" , "Substitute for meat" , "Unfermented soya-bean curd" .)