Try to include the whole vegetable (7)
I believe the answer is:
shallot
'vegetable' is the definition.
(thesaurus)
'try to include the whole' is the wordplay.
'try' becomes 'shot' (shot is a kind of try**).
'to include' indicates putting letters inside.
'the whole' becomes 'all' (I've seen this before).
'shot' going around 'all' is 'SHALLOT'.
(Other definitions for shallot that I've seen before include "Edible onion-like bulb" , "Type of onion" , "Rowing boat" , "It resembles an onion" , "Small onion" .)