Pop group from 3 bringing down a cake (4)
I believe the answer is:
baba
'cake' is the definition.
(baba is a kind of cake)
I don't understand the rest of the clue.
(Other definitions for baba that I've seen before include "Ali . . . . and the Forty Thieves" , "Rum fare" , "a little one" , "small cake" , "Rum-soaked sponge" .)