Grind the biscuits and mix with the soft butter. Line a baking tin with a diameter of 8 3/4″ (22 cm) with baking paper. Distribute the biscuit mixture evenly over the bottom and walls.
Leave in the freezer for 1/2 an hour. In the meantime, prepare the filling. Beat the eggs and sugar with a mixer for about 5 minutes. Add the cottage cheese and mascarpone, vanilla and starch to them. Mix until you get a smooth, homogeneous mixture.
Heat the oven to 320°F (160 °C). Take the form out of the freezer and pour the filling into it. Put it in the oven and bake for about 1 hour. If the cheesecake starts to harden too much on top, cover with aluminum foil.
Once the oven is off, open the oven door slightly and allow the cake to cool inside. After this, put it in the refrigerator.
Before serving, smear it with a thick layer of jam.