How to make
Thaw the puff pastry and roll it out thinly, using the rolling pin in only one direction. Sprinkle the starch at one end of the rolled out puff pastry.
Clean the sour cherries of their pits. Mix them with the blueberries and put them on top of the starch. Sprinkle 2/3 of the sugar on top.
Wrap the dough into a roll, smear it with the beaten egg and sprinkle with the remaining sugar.
Place the roll in an oiled oven dish and bake 25 min. in a preheated 430°F (220 °C) oven.
Take it out of the oven, let it cool a bit and sprinkle with powdered sugar. Cut it into slices and serve warm.