Cool stuff in Leicester (3)
I believe the answer is:
ice
'cool stuff' is the definition.
(ice is cool or cold)
'in leicester' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ICE' is hidden within 'leicester'.
(Other definitions for ice that I've seen before include "Decorate with frosting" , "Glaze" , "kill American" , "Do cake decoration" , "Slippery surface" .)