Green food: the thing in cooked apples (5,3)
I believe the answer is:
split pea
'green food' is the definition.
The definition suggests a singular noun which matches the answer.
'thing in cooked apples' is the wordplay.
'thing' becomes 'it'.
'in' means one lot of letters goes inside another.
'cooked' is an anagram indicator (letters cooked into a new form).
'apples' anagrammed gives 'splpea'.
'it' going inside 'splpea' is 'SPLIT-PEA'.
'the' is the link.
Can you help me to learn more?
(Other definitions for split pea that I've seen before include "A stipple (anag.)" , "Dried vegetable" , "What's ready to add to casserole" , "Pulse" .)