Some additional amontillado needed for mission (5)
I believe the answer is:
alamo
'mission' is the definition.
(famous mission and siege from the Texas revolution)
'some additional amontillado needed' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'ALAMO' is hidden within 'additional amontillado needed'.
'for' is the link.
(Other definitions for alamo that I've seen before include "national monument" , "Famous battle site in Texas" , "Site of a Texas siege, 1836" , "Davy Crockett's last stand" , "Texan battle" .)