A slicer mangled cakes (7)
I believe the answer is:
eclairs
'cakes' is the definition.
(eclair is a type of cake)
'a slicer mangled' is the wordplay.
'mangled' indicates an anagram.
'a'+'slicer'='aslicer'
'aslicer' anagrammed gives 'ECLAIRS'.
(Other definitions for eclairs that I've seen before include "Elongated cream puffs" , "sticky fingers" , "Choux pastries with cream and chocolate icing" , "Cream cakes" , "Oblong pastries" .)