1 Preheat the convection oven to 200°C (approximately 375°F). Grease 4 tartlet pans with butter.
2 Rinse and halve the plums and remove the pits.
3 Separate the eggs and beat the egg whites until stiff. Whip the egg yolks with the sugar and vanilla sugar until creamy and mix with the quark and the lemon zest. Stir the semolina with the baking powder, add to the quark mixture and finally fold in the egg whites. Pour into the tartlet pans and distribute the plums on top, pressing into the surface. Sprinkle the almonds over the top, dust with powdered sugar and bake until golden brown, about 35 minutes.
4 Before serving, sprinkle with powdered sugar again and slice.