The most common and most likely answer to this crossword clue is the 4 letter word CHOC
I've seen this crossword clue in The Daily Telegraph
C
H
O
C
More clues leading to the result CHOC
- Summer treat best to keep cold
- What may be Neapolitan log, last bit polished off
- Cold white wine, almost sweet
- Sweet confection here, or candy, first of all
- Sweet cold white wine not finished
- Cold, white wine unfinished — a little sweet
- Selections involving cold desserts
- Nice thing to eat on hot day that’s excellent, cold inside
- Seaside treat best to eat cold
- Some bar food shortly
Buddy explains!

The straight part
We know that "Sweet" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sweet = choc.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CHOC mean?
CHOC noun- Chocolate