Crumble the biscuits into crumbs, grate or mash them. Melt the butter and gradually pour it into the biscuits, so they butter up well and soften. Put buttered baking paper in an 8″ (20 cm) diameter cake form with removable walls.
Pour in the biscuit mixture and press well. You can put plastic wrap on top and press with your palms to form the biscuit later. Once it's ready, remove the wrap.
Mix the cottage cheese with the sour cream, vanilla (2 packets), powdered sugar, beaten eggs and flour in a separate container. Stir well and pour the resulting mixture over the biscuit layer in the cake form.
Bake in a preheated 230°F (110 °C) oven until ready. The cottage cheese cream needs to harden but not over-bake - approximately 2 hours. Take the ready cake out of the form and smear it with jam. Decorate with meringues or sugar figurines of your choice.