Meanwhile, in a container, mix the water with the cornstarch.
When the mixture reaches a boiling point, add the cornstarch, bring it back to a boil, and cook for 3 minutes, stirring constantly.
Spread each sheet of pie dough with melted butter, add the sour cherry filling sporadically on half of the surface, sprinkle with halva, roll it up, and transfer to a 30 cm diameter pan. Continue with the rest of the ingredients until finished.
Brush the surface with beaten egg and bake at 170°C until golden brown (approximately 45-50 minutes).
