Grow mint, eager to cook (9)
I believe the answer is:
germinate
'grow' is the definition.
(germinating is a kind of growing)
'mint eager to cook' is the wordplay.
'to cook' indicates anagramming the letters.
'mint'+'eager'='minteager'
'minteager' anagrammed gives 'GERMINATE'.
(Other definitions for germinate that I've seen before include "Mere giant (anag) - start to grow" , "Sprout as in a regiment" , "Start to grow - a regiment (anag)" , "(Of seeds) sprout" , "Sprout - develop" .)