Unaccompanied by the best topping (6,5)
I believe the answer is:
single cream
'topping' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'unaccompanied by the best' is the wordplay.
'unaccompanied' becomes 'single' (I've seen this before).
'by' is a charade indicator (letters next to each other).
'the best' becomes 'cream' (as in 'the cream of the crop').
'single'+'cream'='SINGLE CREAM'
Can you help me to learn more?
(Other definitions for single cream that I've seen before include "food" , "Dairy product; cleans grime (anagram)" , "emerges from the dairy" .)