Pleasant piece of grassland (3)
I believe the answer is:
lea
'grassland' is the definition.
(lea is a kind of grassland)
'pleasant piece' is the wordplay.
'piece' indicates the answer is hidden within the clue.
'LEA' is hidden in the letters of 'pleasant'.
'of' acts as a link.
(Other definitions for lea that I've seen before include "Tract of pastureland" , "Pasture, London river" , "area of grassland" , "Meadowland" , "Grazing land" .)