Vegetable cutlet prepared with pea, essentially (7)
I believe the answer is:
lettuce
'vegetable' is the definition.
(lettuce is a kind of vegetable)
'cutlet prepared with pea essentially' is the wordplay.
'prepared with' indicates anagramming the letters.
'essentially' means to look at the middle letters.
The middle letter of 'pea' is 'e'.
'cutlet' mixed up with 'e' makes 'LETTUCE'.
(Other definitions for lettuce that I've seen before include "Salad green" , "Leafy vegetable" , "Cos or iceberg?" , "Plant for the salad bowl" , "Harvest festival item" .)