A helping of crumpet here -- always very light (8)
I believe the answer is:
ethereal
'very light' is the definition.
(I've seen this before)
'a helping of crumpet here always' is the wordplay.
'a helping of' indicates a hidden word (I've seen this in other clues).
'ETHEREAL' is hidden in the letters of 'crumpet here always'.
(Other definitions for ethereal that I've seen before include "There in lea - it looks delicate" , "'Delicate, heavenly (8)'" , "Insubstantial, other-worldly" , "Insubstantial or not of this world" , "Airy or supernatural" .)