Hmm ... but to recast the subject of folklore tales ... (3,5)
I believe the answer is:
tom thumb
'the subject of folklore tales' is the definition.
I can't judge whether this definition defines the answer.
'hmm but to recast' is the wordplay.
'recast' is an anagram indicator.
'hmm'+'but'+'to'='hmmbutto'
'hmmbutto' with letters rearranged gives 'TOM THUMB'.
Can you help me to learn more?
(Other definitions for tom thumb that I've seen before include "Diminutive character of English folklore" , "Fairy story hero" , "Small hero" , "Tiny child of fairy tale" , "Tiny hero of nursery tale - digital?" .)