Put flour, 100 g sugar, salt, 1 egg and butter in flakes into a mixing bowl and knead with the dough hooks of the hand mixer to a smooth dough. Wrap in cling film and chill for 30 minutes. Roll out short pastry on a floured work surface to a circle (32 cm Ø). Line a greased and floured springform pan (26 cm Ø) with the pastry, pressing it up to about 3 cm at the edges. Prick the dough several times with a fork and refrigerate again for about 10 minutes.
Separate 5 eggs in between. Put the egg yolks, quark, sour cream, pudding powder, 300 g sugar and lemon zest into a mixing bowl and mix to a homogenous mass with the whisks of the hand mixer. Beat the egg white until stiff. Fold into the quark mixture in portions. Pour the mixture onto the short pastry and smooth it down. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: not suitable/ gas: level 2) for 65-75 minutes. After half of the baking time cover the cake if necessary. Take it out of the oven, place it on a cake rack and remove it from the edge of the springform pan with a knife. Leave to cool in the mould. Remove the cooled down cake from the tin and place it on a cake plate.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: not suitable/ gas: level 2) for 65-75 minutes. After half of the baking time cover the cake if necessary. Take it out of the oven, place it on a cake rack and remove it from the edge of the springform pan with a knife. Leave to cool in the mould. Remove the cooled down cake from the tin and place it on a cake plate. Dust the middle of the cake with icing sugar and decorate with lemon balm. Whipped cream tastes good with it
waiting time approx. 6 hours