I'm using Jenkins 1.596 with ClearCase Plug-in 1.5.3.
SCM is UCM ClearCase.
My job is currently polling against the stream and if new work has been delivered, it will create a new view.
1/ Is it possible to poll for the event of baseline recommendation?
Not that I know of.
2/ is it possible to instruct it to use the recommended baseline?
No: an UCM view is by definition selecting the LATEST versions on the branch associated to that stream.
Another approach would be to have a sub-stream, which you could then rebase: by default, the rebase should pick the recommended baseline of the parent stream.
The job could then used that rebased view.
But that means a non-standard job UCM setting, with a non-standard polling policy, like a first job checking if there is any new baseline (job launched every few minutes), and if there is one, calling a second job (for the rebase)