That girl tucks into a new pasty (5)
I believe the answer is:
ashen
'pasty' is the definition.
(both can mean pale)
'that girl tucks into a new' is the wordplay.
'that girl' becomes 'she' (I've seen this in another clue).
'tucks into' is an insertion indicator.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'a'+'n'='an'
'she' put inside 'an' is 'ASHEN'.
(Other definitions for ashen that I've seen before include "So vampire might appear" , "Unhealthily pale" , "Anaemic-looking" , "Deathly pale" , "lacking in colour" .)