Separate eggs. Beat the egg whites and 3 tablespoons of water until stiff, adding 100 g of sugar. Stir in egg yolks. Mix flour, starch and baking powder and fold into the mixture. Line a baking tray with baking paper and spread the mixture evenly on top. Bake the sponge cake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 8 minutes.
Remove the sponge cake from the oven and turn it over onto a tea towel sprinkled with sugar. Remove the baking paper and roll up the sponge cake from the long side. Soak the gelatine in cold water. Whip 400 g cream, plum brandy, 1 tablespoon sugar and vanillin sugar until stiff. Squeeze the gelatine and dissolve. Stir in 3 tablespoons of whipped cream, then stir into the remaining cream and chill. Roll out the sponge roll and spread with 6-7 tablespoons of plum jam. Spread the whipped cream on the plum jam and roll up again. Put the sponge roll in a cool place for 1-2 hours. Wash and stone the plums and cut them into 15 slices. Dilute 1 tablespoon plum puree with a little water. Whip 100 g whipped cream until stiff and fill into a piping bag with a small star-shaped spout.
Spread the whipped cream on the plum jam and roll up again. Put the sponge roll in a cool place for 1-2 hours. Wash and stone the plums and cut them into 15 slices. Dilute 1 tablespoon plum puree with a little water. Whip 100 g whipped cream until stiff and fill into a piping bag with a small star-shaped spout. Pour 15 cream tuffs onto the sponge roll. Decorate the tuffs with some plum puree, plum wedges and lemon balm. Cut the sponge roll into 15 pieces
2 hours waiting time