Gee, hot in butter (4)
I believe the answer is:
ghee
'butter' is the definition.
(I know that ghee is a type of clarified butter)
'gee hot in' is the wordplay.
'hot' becomes 'h' (abbreviation eg on taps).
'in' is an insertion indicator.
'gee' placed around 'h' is 'GHEE'.
(Other definitions for ghee that I've seen before include "type of butter" , "Form of clarified butter" , "clarified product" , "Clarified butter used in Indian cookery" , "Use it to cook" .)