Pig out, finding this food (7)
I believe the answer is:
truffle
'food' is the definition.
(truffle is a kind of food)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for truffle that I've seen before include "Rich food" , "Fretful for tasty underground fungus" , "2 (anag)" , "Fretful (anag)" , "Rich-flavoured fungus that grows undergrond" .)