Goal I have to produce vegetable (6)
I believe the answer is:
endive
'vegetable' is the definition.
(I know that endive is a type of leaf vegetable)
'goal i have' is the wordplay.
'goal' becomes 'end' (both can mean a purpose).
'i have' becomes 'I've' (contraction of 'I have').
'end'+'ive'='ENDIVE'
'to produce' acts as a link.
(Other definitions for endive that I've seen before include "Curly-leaved plant used as salad" , "Edible plant" , "Chicory-type salad vegetable" , "Salad plant related to chicory" , "Plant used in salads" .)