Impatient exclamation from Scot splitting cheese roll (7)
I believe the answer is:
brioche
'roll' is the definition.
(brioche is a kind of roll)
'impatient exclamation from scot splitting cheese' is the wordplay.
I cannot really understand how this works, but
'exclamation' could be 'och' (I have seen 'Scots exclamation ' mean 'och' so perhaps 'exclamation' could also mean 'och') and 'och' is present in the answer.
'cheese' could be 'brie' (Brie is an example) and 'brie' is found within the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for brioche that I've seen before include "Sponge cake or roll" , "Soft roll made of light yeast dough" , "Small French roll" , "Idol" , "French cake-like bread" .)