Brought back up to see very loud assistant's attempt, which is pretty flaky (4,6)
I believe the answer is:
puff pastry
'is pretty flaky' is the definition.
I can't judge whether this defines the answer.
'brought back up to see very loud assistant's attempt' is the wordplay.
'brought back' says the letters should be written in reverse.
'to see very loud' becomes 'ff' (musical abbreviation for 'fortissimo', very loud).
'assistant's' becomes 'PA's' (personal assistant).
'attempt' becomes 'try' (synonyms).
'up' written backwards gives 'pu'.
'pu'+'ff'+'pas'+'try'='PUFF PASTRY'
'which' acts as a link.
Can you help me to learn more?
(Other definitions for puff pastry that I've seen before include "Lightweight food" , "It's used for vol-au-vents" .)