The most common and most likely answer to this crossword clue is the 11 letter word PRECIPITATE
I've seen this crossword clue in Financial Times
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More clues leading to the result PRECIPITATE
Buddy explains!

The straight part
We know that "Pour/egg on/snow" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pour/egg on/snow = precipitate.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 PRECIPITATE mean?
PRECIPITATE verb- To make something happen suddenly and quickly.
- To throw an object or person from a great height.
- To send violently into a certain state or condition.
- To come out of a liquid solution into solid form.
- To separate a substance out of a liquid solution into solid form.
- To have water in the air fall to the ground, for example as rain, snow, sleet, or hail; be deposited as condensed droplets.
- To cause (water in the air) to condense or fall to the ground.
- To fall headlong.
- To act too hastily; to be precipitous.
- Headlong; falling steeply or vertically.
- Very steep; precipitous.
- With a hasty impulse; hurried; headstrong.
- Moving with excessive speed or haste.
- Performed very rapidly or abruptly.
- A product resulting from a process, event, or course of action
- A solid that exits the liquid phase of a solution