The most common and most likely answer to this crossword clue is the 7 letter word GATEAUX
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More clues leading to the result GATEAUX
Buddy explains!

The straight part
We know that "What are grand with an afternoon meal and posh times?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what are grand with an afternoon meal and posh times? = gateaux.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 GATEAUX mean?
GATEAUX noun- A rich, usually iced, cake.
- A dish of minced meat made up like a pudding, and boiled in a shape or mould.