I'm surprised to get into starters of brie, langoustine, escargots, unusually: fancy, French food! (6,4)
I believe the answer is:
cordon bleu
'french food' is the definition.
'i'm surprised to get into starters of brie langoustine escargots unusually' is the wordplay.
'i'm surprised' becomes 'cor' (old-fashioned UK expression of shock or awe).
'to get into' becomes 'don' (synonyms).
'starters of' says to take the initial letters.
The first letters of 'brie langoustine escargots unusually' is 'bleu'.
'cor'+'don'+'bleu'='CORDON BLEU'
'fancy' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for cordon bleu that I've seen before include "High-class cookery" , "Of a very high standard (food)" , "High class chef" , "Old bouncer (anag)" , "Highest class (cooking)" .)