Provider of zest in cocktail or water in spirit (6,4)
I believe the answer is:
orange peel
'provider of zest' is the definition.
'orange peel' can be an answer for 'zest' (I've seen this in another clue). I am not sure about the 'provider of' bit.
'cocktail or water in spirit' is the wordplay.
I cannot really see how this works, but
'or' is found in the answer.
'water' could be 'pee' (synonyms) and 'pee' is found within the answer.
'spirit' could be 'angel' and 'angel' is present in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for orange peel that I've seen before include "Bit of fruit" , "Rind often candied" , "Pithy stuff" .)