Chocolate cake made by caterers, tho' badly (11)
I believe the answer is:
sachertorte
'chocolate cake' is the definition.
(I know that Sachertorte is a type of chocolate cake)
'by caterers tho' badly' is the wordplay.
'by' is a charade indicator (letters next to each other).
'badly' is an anagram indicator.
'caterers' put after 'tho' is 'thocaterers'.
'thocaterers' anagrammed gives 'SACHERTORTE'.
'made' acts as a link.
(Other definitions for sachertorte that I've seen before include "piece of cake for Strauss" , "German gateau" , "Chocolate cake" .)