Green sauce for pasta (5)
I believe the answer is:
pesto
'green sauce for pasta' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pesto that I've seen before include "sauce involving Basil" , "Pasta sauce mainly of basil and cheese" , "Sauce of basil, pine nuts, etc" , "Saucy work" , "A sauce served with pasta" .)