For the plum cake with cream glaze, wash the plums, remove the seeds and cut into quarters. Preheat the oven to 175 degrees Celsius.
Cream the soft butter with the sugar, vanilla sugar, grated lemon zest and a pinch of salt. Beat in the eggs one at a time until well blended.
Sift the flour, baking powder, cornflour and cinnamon together and gently stir into the butter mixture. Spread the dough on a baking tray (greased or with baking paper), place the plums on top and place on the middle shelf in the preheated oven.
In the meantime, mix the glaze and spread it over the dough after 15 minutes. Bake for another 35-40 minutes. Serve sprinkled with powdered sugar.