The most common and most likely answer to this crossword clue is the 5 plus 4 letter word SWISS ROLL
I've seen this crossword clue in The Daily Telegraph
S
W
I
S
S
R
O
L
L
More clues leading to the result SWISS ROLL
- Tube? — it’s often jam packed
- Refuse to welcome tourists regularly coming back for cake
- Cake makes tongue register
- Will Ross’s cooked a cake
- Possibly Federer’s turn to provide cake
- Tumble down the ski slopes maybe for teatime treat?
- Poor Ross, covered in pigfeed, gets a sponge
- Tell maybe part that’s been picked up in cake?
- Jammed cylinder
- Helvetian aerobatic stunt with a type of cake
Buddy explains!

The straight part
We know that "Jammed cylinder" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case jammed cylinder = swiss roll.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.