Place biscuits into a freezer bag and crumble with a rolling pin. Combine with cocoa and melted butter. Press crumb mixture onto the bottom of springform pan and bake in preheated oven at 180°C (approximately 350°F) for 10 minutes. Remove from oven and cool. Turn down oven temperature to 160°C (approximately 325°F).
Melt crushed chocolate with orange juice in a saucepan, stirring. Remove from heat and stir in orange liqueur.
Combine quark, mascarpone, sugar and vanilla seeds. Add eggs, one at a time, and mix well. Halve cream mixture and combine one half with chocolate. Butter sides of springform pan.
Spread half of white cream onto biscuit base, top with one dollop of chocolate cream and spread it outwards (leaving white cream at the edges). Continue adding white and chocolate creams alternately, making circles.
Bale cake in preheated oven at 160°C (approximatley 325°F) for 60 minutes. Allow to cool and refrigerate overnight. Serve.