Place a kitchen towel in a colander and place the colander over a bowl to collect any draining liquid. Pour yoghurt on top of the kitchen towel. Set in refrigerator for 12 to 24 hours. Use this yoghurt curd-like cream cheese.
Mix biscuit crumbs with 1 teaspoon sugar and butter. Spread mixture in the bottom of a 23cm round springform tin.
Mix yoghurt curd with 200g, eggs and vanilla. Pour over base.
Bake at 170 C / Gas 3 for 70 minutes or until done when checked with skewer. Let sit 24 hours before serving.