For the plum tiramisu, wash, dry and pit the plums. Puree half of them with a hand blender. Whip the Cremefine, mix well with the powdered sugar, vanilla sugar and cinnamon.
Add the juice of half a lemon. Stir in the mascarpone by the spoonful and add the pureed plums. Cut the remaining plums into small pieces and mix them into the mixture as well.
Place a layer of sponge cake in a baking dish, then spread the plum cream on top, then sponge cake, cream, etc. until everything is used up. Finish with the cream. Refrigerate for a few hours or overnight.