The most common and most likely answer to this crossword clue is the 8 letter word COSTARDS
I've seen this crossword clue in The Daily Telegraph
C
O
S
T
A
R
D
S
More clues leading to the result COSTARDS
Buddy explains!

The straight part
We know that "apples" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case apples = costards.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 COSTARDS mean?
COSTARDS noun- A large cooking apple.
- The tree on which large cooking apples grow.
- The human head.