Gold-rich land girl in the Spanish Party (8)
I believe the answer is:
eldorado
'gold-rich land' is the definition.
I can't judge whether this definition defines the answer.
'girl in the spanish party' is the wordplay.
'girl' becomes 'dora' (girl's name).
'in' means one lot of letters goes inside another.
'the spanish' becomes 'el' ('the' in Spanish).
'party' becomes 'do' (do is a kind of party).
'el'+'do'='eldo'
'dora' going within 'eldo' is 'ELDORADO'.
Can you help me to learn more?
(Other definitions for eldorado that I've seen before include "rich land, so many thought" , "source of wealth" , "city of riches" , "wealthy location" , "city, apparently lost" .)