Girl has an unusual idea of earthly paradise (7-2)
I believe the answer is:
shangri-la
'earthly paradise' is the definition.
(I've seen this before)
'girl has an unusual' is the wordplay.
'unusual' indicates an anagram.
'girl'+'has'+'an'='girlhasan'
'girlhasan' anagrammed gives 'SHANGRI-LA'.
'idea of' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for shangri-la that I've seen before include "Imaginary earthly paradise" , "Tibetan paradise created by James Hilton in novel 'Lost Horizon'" , "Milk" , "Hangs liar in idyllic Tibetan country created by James Hilton" , "Fabled utopia" .)