I'm surprised, eating hot curry ingredient (4)
I believe the answer is:
ghee
'curry ingredient' is the definition.
(common ingredient in South Asian cooking)
'i'm surprised eating hot' is the wordplay.
'i'm surprised' becomes 'gee' (exclamation of surprise).
'eating' means one lot of letters goes inside another.
'hot' becomes 'h' (abbreviation eg on taps).
'gee' enclosing 'h' is 'GHEE'.
(Other definitions for ghee that I've seen before include "Clarified butter used in Indian cookery" , "Indian form of butter" , "Clarified butter used in Indian cooking" , "Form of clarified butter" , "clarified product" .)