The most common and most likely answer to this crossword clue is the 5 plus 5 letter word RINGO STARR
I've seen this crossword clue in Financial Times
R
I
N
G
O
S
T
A
R
R
More clues leading to the result RINGO STARR
Buddy explains!

The straight part
We know that "Kitchen expert" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case kitchen expert = ringo starr.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.