The most common and most likely answer to this crossword clue is the 10 letter word BATTENBERG
I've seen this crossword clue in Financial Times
B
A
T
T
E
N
B
E
R
G
More clues leading to the result BATTENBERG
Buddy explains!

The straight part
We know that "German nobles/cake" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case german nobles/cake = battenberg.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 BATTENBERG mean?
BATTENBERG noun- Alternative form of Battenberg