Prepare the dough from flour, BABIČKA butter, and BABIČKA sour cream. Let it rest in the refrigerator for at least half an hour. Meanwhile, mix the curd cheese, NIVA ORIGINÁL cheese, and a pinch of salt. Roll out the rested dough and cut out equal circles. Fill with the prepared mixture and join two opposite sides. Transfer to a baking tray lined with baking paper and brush with egg. Bake at 200°C for approximately 10 to 15 minutes.