Finger-shaped cake (6)
I believe the answer is:
eclair
'finger-shaped cake' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for eclair that I've seen before include "Soft cream cake" , "Finger-shaped cake with cream and chocolate" , "A long thin cake with chocolate covering" , "Finger-shaped, chocolate-iced, cream-filled cake" , "Long (but not long-lasting) cake" .)