Halve the plums, remove the stones. Run some butter across all of the inside of the pan, add the halved plums upside down into the pan. Sprinkle sugar over the plums, cook on medium heat for about 10 - 15 minutes. Keep an eye on them so that they dont burn.
In the meantime make the batter. Stir all the other ingredients together. Adding the milk, cream or condensed milk little by little.
Make sure that it neither becomes to thin or thick. It should just drip in strands from the whisk. Pour the batter over the plums turn the heat down to the lowest heat, cover with a lid.
Bake for about 30 minutes or so, until set and a skewer comes clean. Cool down slightly. Carefully turn it over using the plate that fits your pan and you want to serve from. Sprinkle with cinnamon and sieved icing sugar if you like.
