Melt the butter. Finely grind the biscuits in the universal chopper. Pour into a bowl and mix with butter. Lightly brush a springform pan (approx. 26 cm Ø) with oil. Put biscuit crumbs into the form and press them down to a smooth base. Place the tin in a cool place for about 30 minutes.
Boil up 100 g of cream separately in small pots. Chop dark and white chocolate separately and melt cream in one pot each. Stir the milk into the dark chocolate cream, let everything cool down a little
Beat the eggs and sugar with the whisk of the hand mixer until foamy. Stir in curd and starch. Halve the mixture and stir into one half of cocoa and dark chocolate cream. Stir the light chocolate cream into the other. Fill both masses alternately in blobs on the crumb base. Pull through with a fork, so that a marble pattern is created
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 50-60 minutes. Finally, cover with foil if necessary. Leave to rest for approx. 15 minutes in the switched off oven. Loosen the cake edge with a knife and let it cool down in the mould. To serve, dust the edge with icing sugar
waiting time approx. 2 1/4 hours