Wash, stone and halve the plums. Mix the fat, 100 g sugar and a packet of vanilla sugar with the whisk of the hand mixer. Separate 2 eggs. Set the egg whites aside.
Gradually add 2 eggs and 2 egg yolks to the mixture. Mix flour and baking powder. Pour onto the egg mixture and stir. Stir in milk. Fill the dough into a greased and breadcrumbed springform pan (26 cm Ø) and smooth it down.
Spread the plums on top and dust with cinnamon. Bake in the preheated oven (electric oven: 200 °C/ gas: level 3) on lowest level for about 30 minutes. In the meantime, beat egg whites until stiff, add lemon juice.
Let the remaining sugar trickle in. Take the cake out of the oven and spread the beaten egg white mixture on top. Bake for another 10 minutes. In the meantime, roast the flaked almonds without fat in a small pan. Remove the cake.
Let it cool down on a cake rack. Serve sprinkled with flaked almonds. Makes about 12 pieces.