Kitchen utensil seen in show: his knife (5)
I believe the answer is:
whisk
'kitchen utensil' is the definition.
(I've seen this before)
'in show his knife' is the wordplay.
'in' indicates the answer is hidden within the clue.
'WHISK' is hidden within 'show his knife'.
'seen' acts as a link.
(Other definitions for whisk that I've seen before include "Beat briskly" , "Beat to a froth" , "Kitchen utensil" , "Whipping utensil" , "Kitchen mixer" .)