The most common and most likely answer to this crossword clue is the 16 letter word TOAD-IN-THE-HOLE
I've seen this crossword clue in The Guardian
T
O
A
D
-
I
N
-
T
H
E
-
H
O
L
E
Buddy explains!
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.