Wash, halve and stone the plums. Separate eggs. Mix flour, 400 g sugar, vanillin sugar, baking powder and 1 pinch of salt. Add the egg yolks and butter in pieces. First knead into crumbles with the dough hooks of the hand mixer, then with your hands. Put 2/3 of the crumbles into the greased fat pan of the oven and press to a smooth base. Cover with plums and spread the remaining crumbles on top.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 20 minutes. Beat the egg whites until very stiff, add 1 pinch of salt and 150 g sugar. Finally, fold in the cinnamon. Pour into a piping bag with star-shaped spout and squirt tuffs onto the cake. Bake for about 10 minutes at the same temperature. Let it cool down. Cut into pieces, sprinkle tuffs with red sugar
waiting time approx. 1 1/2 hours