In a 21 inch tart pan, cut and place the plums. Sprinkle one tablespoon of sugar over the plums. Place the butter in between, spread around.
Microwave for 4 minutes to soften the plum.
Meanwhile, preheat the oven to 180 degrees.
Whisk together the remaining sugar and all the ingredients in a mixing bowl till smooth and homogenous.
Take out the tart pan from the microwave and pour the sauce all over. It will be filled to the brim.
Carefully place into the preheated oven and bake for 15 minutes. Switch off the oven and leave the clafoutis in till the oven cools down.
This will help the custard base to set. Serve warm out of the oven...