Preheat your oven to 350˚F/180˚C, combi steam setting. If your oven has variable steam settings, use 100% steam. If not, don't worry! Just set to combi steam at the correct temperature and the oven will figure out the humidity for you.
Put all your fruit into a dish where the pieces can be packed in fairly snugly. If you have enough space, lay it in cut-side up. If you went a little overboard on your fruit quantity, like I often do, just tuck it all in standing on end.
Halve the vanilla bean and tuck it under the fruit. Sprinkle with sugar – in general, I find the plums need a little more, other fruits a little less. I prefer to err on the side of less sweet so rarely use the entire half cup. And I’ve done very sweet apricots with absolutely no sugar, which was just fine, although the lack of added sugar means they only last a couple of days in the fridge.
Put the dish, uncovered, in the oven and cook for around 20 minutes, by which time the fruit should be bubbling, softened, syrupy and just starting to brown at the edges. If it’s not soft enough for you, put it back in for a few more minutes.
Cool to room temperature in the baking dish, then transfer to the fridge for up to 4 days or the freezer for a couple of months.