As menu, sadly, not quite right, dined outside (1,2,5)
I believe the answer is:
a la carte
'outside' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?
'as menu sadly not quite right dined' is the wordplay.
I cannot quite understand how this works, but
'as' could be 'ala' (French 'a la' - 'in the style of') and 'ala' is located in the answer.
'menu' could be 'carte' (synonyms) and 'carte' is found within the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for a la carte that I've seen before include "way of ordering things" , "Showing individual price of fare" , "Menu with individually-priced dishes" , "Not table d'hote" , "freedom to choose" .)