The most common and most likely answer to this crossword clue is the 4 letter word FARL
I've seen this crossword clue in Financial Times
F
A
R
L
More clues leading to the result FARL
Buddy explains!

The straight part
We know that "cake" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cake = farl.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 FARL mean?
FARL noun- A quarter of a thin oatmeal or flour cake.
- Any such cake or bread, now particularly used for Irish specialities as soda farls and potato farls.
- To lower, roll up and secure (something, such as a sail or flag)