Brainy part, cooking eel crumble (10)
I believe the answer is:
cerebellum
'brainy part' is the definition.
'cerebellum' can be an answer for 'part' (cerebellum is a kind of part). I'm unsure of the 'brainy' bit.
'cooking eel crumble' is the wordplay.
'cooking' is an anagram indicator (cook can mean to falsify or distort).
'eel'+'crumble'='eelcrumble'
'eelcrumble' anagrammed gives 'CEREBELLUM'.
Can you help me to learn more?
(Other definitions for cerebellum that I've seen before include "motor controller" , "bit of brain" , "part of the brain" .)