Preheat oven 180 C. Lightly grease a baking dish with a little of the butter, then spread a more onto both sides of the bread. Put the bread in the dish and arrange the plums on top, cut side up.
Slit the vanilla pod longways and scrape out the seeds, combine them with the remaining butter, smear all over the plums. Drizzle the honey or maple syrup over. Put the empty vanilla pods on top of the plums.
Bake for 25 - 35 minutes until plums are cooked and bread is golden, keep an eye on your dish, it will turn quick. Serve with cream, ice cream or greek yoghurt