Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Line the bottom of a springform pan (26 cm Ø) with baking paper. Mix flour and baking powder. Separate the eggs. Beat the egg whites and 1 pinch of salt until stiff with the whisks of the mixer, adding 150 g sugar and 1 packet of vanilla sugar. Stir in the egg yolks one by one. Sift the flour mixture on top and fold in carefully. Pour the sponge mixture into the mould and smooth it down. Bake in a hot oven for about 30 minutes. Let it cool down on a cake rack.
For the cream, mix quark, mascarpone, 100 g sugar and 1 packet of vanilla sugar with the whisks of the mixer for about 2 minutes. Put it in a cold place.
For the bumblebees, chop the chocolate and melt it in a hot water bath. In the meantime, drain the apricots in a sieve. Place 5 pieces on a cake rack, dab dry thoroughly with kitchen paper. Pour melted chocolate into a disposable piping bag and cut off a small corner. Spray strips over the apricots, leaving the front third free. Lightly prick twice with a sharp knife on the back of the fruit. Insert the flaked almonds as wings. Stick 2 sugar eyes each with some chocolate on the apricots. Put the bumblebees in a cool place. Finely mash the remaining apricots.
Remove the sponge cake from the mould and cut through horizontally twice. Place the bottom cake layer on a cake plate. Spread half of the cream on top. Place the middle cake layer on top and spread the rest of the cream, except for 2 tbsp. Place the top cake layer on top. Spread the rest of the cream on the surface. Smooth out the edge. Spread the bumblebees and apricot puree on the cake.