The most common and most likely answer to this crossword clue is the 6 letter word EGGIER
E
G
G
I
E
R
Buddy explains!
The straight part
We know that "richer in yolk" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case richer in yolk = eggier.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 EGGIER mean?
EGGIER adjective- Covered with or dipped in egg.
- Resembling eggs in some way.
- Of or relating to an egg or eggs.
- Slightly annoyed.