A chef initially varied menu, showing insight (6)
I believe the answer is:
acumen
'insight' is the definition.
(I've seen this in another clue)
'a chef initially varied menu' is the wordplay.
'initially' indicates taking the first letters.
'varied' indicates an anagram.
The first letter of 'chef' is 'c'.
'menu' anagrammed gives 'umen'.
'a'+'c'+'umen'='ACUMEN'
'showing' acts as a link.
(Other definitions for acumen that I've seen before include "Wit" , "intuition" , "Quick intelligence" , "The ability to make good and quick decisions" , "Being sharp" .)