Something delicious in Rio: samba that rocks! (8)
I believe the answer is:
ambrosia
'something delicious' is the definition.
I can't tell whether this definition defines the answer.
'rio samba that rocks' is the wordplay.
'that rocks' indicates an anagram.
'rio'+'samba'='riosamba'
'riosamba' with letters rearranged gives 'AMBROSIA'.
'in' is the link.
Can you help me to learn more?
(Other definitions for ambrosia that I've seen before include "Food of the gods in Greek mythology" , "Beebread" , "meal fit for gods" , "Food and drink of gods" , "food for Olympians" .)