OK, so I was wading my way through Mzart's Clarinet Concerto, 2nd movement, when suddenly, there is a Bb, with a fermata, with Cad. written next to it.

Alright, I thought.....*screamed*, and ran away, leaving the chair spinning....

So, how do we go about writing a Cadenza? Any thought and ideas welcomed...

Have a listen to my recording on YAP's site. The one I did there is quite common, and simple. It's used in the quintet as well in a similar place. I'll write out some from other recordings I've got some other time.

Just let yourself go and play like Giora Feldman for a few bars and then back to the Mozart!

There are many similarities between the slow movements of the quintet and the concerto, so playing the cadenza from the quintet sounds OK if you're stuck. The cadenza used by Jack Brymer was similar to that written into the quintet, and if that approach is good enough for him, it'll do for me!

What you do ultimately has to be your decision; I'd advise something concise and not too flashy. The cadenza my teacher wrote for me when I learnt it goes:
written Bb, which is tied to the Bb which is the first quaver of the cadenza, then A C Bb A G / F E D C Bnat C /

all equal quavers, with / being imaginary barlines.

Hope it makes sense written out like this. It's simple yet effective, and I still use it ('cos I've got no imagination of my own!).

D - that sounds cool! I will talk to my teacher, and see if he has any ideas.

What Deborah suggests sounds perfect. It is an eingang rather than a cadenza so requires a gentle florish rarther than the flashy pyrotechnicks (sorry spelling gone to pot and dictionary not at hand you know what word I mean) normally associated with a cadenza

I thought the two eingange occured in the first movement of the concerto and that it was an actual cadenza in the 2nd mvmt? Perhaps not! lol although thinking about it theres no modulation which would make it an eingang not a cadenza....ok forget I started mumbling about this! hehe