Melt 50 g butter. Crumble cookies in a freezer bag and mix with the melted butter. Line the bottom of a springform pan (26 cm Ø) with baking paper. Spread butter-cookie crumbs on the bottom, press them firmly to a smooth base and chill.
Separate eggs. Beat egg whites until stiff. Cream 75 g butter, sugar and vanillin sugar. Stir in the egg yolks one by one. Stir the cheesecake aid and quark into the mixture. Carefully fold in the beaten egg white.
Fill into the springform pan and smooth it down. Drain the apricots and spread on the mixture. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 1 hour.
Loosen the edge of the springform pan with a knife and let the cheesecake rest for 20 minutes in a switched off oven. Remove from the oven and let it cool down on a rack. Remove the springform pan. Let the cake cool down on a grid.
Decorate with lemon balm.