A recepie from my mom. It is only one example for a possilbe filling. You can also put some ham and boiled eggs in it or anything you like.
200 g cheese
150 g liver pate
2 tablespoons butter
1 teaspoon paprika paste
1 boiled egg
2 sour cucumber
Melt cheese over steam or in microwave.
When melted form a rectangle on folie.
Mix liver pate with butter, paprika paste and pepper.
Add chopped cucumber and egg.
Roll and keep in fridge for 3 hours.