One end of cake covered in stuff from the dairy (6,5)
I believe the answer is:
single cream
'stuff from the dairy' is the definition.
(dairy product)
'one end of cake covered in' is the wordplay.
'one' becomes 'single' (synonyms).
'end of cake' becomes 'cream' (I can't justify this - if you can you should give a lot more credence to this answer).
'covered in' means one lot of letters go next to another (some letters go on top of or cover others).
'single'+'cream'='SINGLE CREAM'
(Other definitions for single cream that I've seen before include "Dairy product; cleans grime (anagram)" , "food" , "emerges from the dairy" .)