The most common and most likely answer to this crossword clue is the 11 letter word NINETY-NINE
I've seen this crossword clue in The Guardian
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More clues leading to the result NINETY-NINE
Buddy explains!
The straight part
We know that "ice cream" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ice cream = ninety-nine.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 NINETY-NINE mean?
NINETY-NINE noun- A traditional British ice cream cone with a flaky chocolate bar inserted, usually made with soft serve.
- A simple card game with a running total, players dropping out if they would be forced to bring the total above ninety-nine.
- The cardinal number immediately following ninety-eight and preceding one hundred.