I'm surprised: is brown sauce put into horrible local dish? (7,5)

I believe the answer is:

cornish pasty

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'local dish?' is the definition.
'cornish pasty' can be an answer for 'dish?' (I have seen 'Regional dish ' mean 'cornish pasty' so perhaps 'dish' could also mean 'cornish pasty'). I am not certain of the 'local' bit.

'i'm surprised is brown sauce put into horrible' is the wordplay.
'i'm surprised' becomes 'cor' (old-fashioned UK expression of shock or awe).
'brown sauce' becomes 'HP' (HP is a condiment brand).
'put into' indicates putting letters inside.
'horrible' becomes 'nasty' (I've seen this before).
'is'+'hp'='ishp'
'ishp' inserted into 'nasty' is 'nishpasty'.
'cor'+'nishpasty'='CORNISH PASTY'

Can you help me to learn more?

(Other definitions for cornish pasty that I've seen before include "West Country dish" , "Regional dish" , "local delicacy" , "British regional savoury snack" , "West Country speciality food" .)

I've seen this clue in The Telegraph.

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