Preheat oven to 180c 350fSlice the rhubarb into chunks and place on a baking tray, drizzle over honey, orange blossom water, orange juice and zest. Slice the vanilla bean and scrape out some of the seeds and mix with the juice in the pan, add the pod to the tray and roast for 10 minutes. Turn the pan and bake for another 5, or until the rhubarb is soft but holds its shape.