For the base, grind the cookies in a blender, add the melted butter, mix, press into an 18 cm pan and build up the sides. Refrigerate the pan until you're ready to pour in the filling.
With a whisk, mash and rub the cottage cheese with salt and sugar, add the sour cream and cornstarch, mix with a spatula, then add the eggs one at a time.
Split the mixture into 2 parts; add the melted chocolate and cocoa to one - now you have two colors.
Take out the pan and alternately pour 2 tbsp of each colored mixture into the center to create a zebra pattern.
Bake for 30 minutes at 180 C, then, without opening the oven, another 30 minutes at 150 C.
Turn off the oven and let the cheesecake cool inside it, then refrigerate for at least 4 hours, ideally overnight. Enjoy!