Prepared ten quiches -- last lacking style (9)
I believe the answer is:
technique
'style' is the definition.
(thesaurus)
'prepared ten quiches last lacking' is the wordplay.
'prepared' indicates anagramming the letters.
'last lacking' means to remove the last letter.
'ten'+'quiches'='tenquiches'
'tenquiches' with its final letter removed is 'tenquiche'.
'tenquiche' anagrammed gives 'TECHNIQUE'.
(Other definitions for technique that I've seen before include "Method of carrying out a task" , "Proficiency" , "Working method for tin cheque" , "Practical procedure" , "Method for doing something" .)