Salt in ravioli, but never penne, ultimately (5)
I believe the answer is:
nitre
'salt' is the definition.
(nitre is a kind of salt)
'in ravioli but never penne ultimately' is the wordplay.
'ultimately' indicates one should take the final letters.
The final letters of 'in ravioli but never penne' are 'NITRE'.
(Other definitions for nitre that I've seen before include "fertiliser" , "Inert (anag) - saltpetre" , "Gunpowder ingredient" , "safeguard against decay" , "Otherwise saltpetre" .)