Knead flour, 100 g sugar, 1 pinch of salt, butter in pieces and 1 egg to a smooth dough. Roll out to a circle (approx. 32 cm Ø) on a floured surface. Grease a springform pan (26 cm Ø). Carefully place the dough sheet into the tin with the help of the cake roll. Pull up the rim approx. 3 cm and press on. Prick the base several times with a fork.
Chill for about 30 minutes. Roughly chop the chocolate and melt in a bowl over a warm water bath. Separate 3 eggs. Beat egg white and 1 pinch of salt until stiff. Put the quark and sour cream in a bowl. Stir in egg yolks, milk, lemon juice, 150 g sugar, pudding and sauce powder one after the other. Carefully fold in the beaten egg white. Halve the mixture. Carefully stir the liquid chocolate into one half. Pour masses alternately with 2 tablespoons always in the middle (on the same spot) of the dough. Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) on the lower shelf for 40-50 minutes. After about 35 minutes of baking time cover the cake with aluminium foil.
Carefully fold in the beaten egg white. Halve the mixture. Carefully stir the liquid chocolate into one half. Pour masses alternately with 2 tablespoons always in the middle (on the same spot) of the dough. Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) on the lower shelf for 40-50 minutes. After about 35 minutes of baking time cover the cake with aluminium foil. Leave the cake to cool in the switched-off oven with the door open (preferably overnight). Remove the cake from the tin
waiting time approx. 1 1/2 hours