1. Preheat your oven to 350°F (180°C).

For the Soup

1. Clean the plums, remove the stones, and cut them into slices or quarters, depending on the size of your oven dish.
2. In a bowl, beat the eggs together with the blond cane sugar until well combined.
3. In a separate bowl, dilute the cornstarch in the cold milk. Add the all-purpose flour and cornstarch mixture to the egg and sugar mixture. Stir until smooth.
4. Add the vanilla quark to the mixture. If you cannot find vanilla quark, use regular quark and add the seeds of one vanilla pod. Check the sweetness and add more sugar if needed. Finally, add ground cinnamon to taste and the zest of one lime. Mix everything until well combined.
5. Grease four or five small ramekins (or one larger dish) with butter. Sprinkle sugar inside the ramekins and remove any excess.
6. Divide the plum slices evenly between the prepared ramekins. Fill them generously.
7. Pour the egg mixture over the plums in each ramekin.
8. Place the ramekins in the preheated oven and bake for 40-45 minutes until the tops are golden brown.
9. Remove the clafoutis from the oven and let them cool. Serve lukewarm or cold. Optionally, sprinkle with icing sugar before serving.