For the apple pieces, peel the apples, remove the core and cut into small pieces. Place in a saucepan, sprinkle with cinnamon and steam over low heat until soft.
Finally, steam without a lid (so that the juice boils away a bit). Let cool.
Roll out the puff pastry and divide into 10 pieces, brush the edges with water. Make 4 slits in one half of the pastry with a pastry wheel, put some of the cold steamed apples on the other half and put 1 teaspoon of currant jam on top.
Fold and press together with a fork. Place on a coated baking tray and brush with water. Bake in the preheated oven at 200 °C for about 20 minutes until golden.
Mix the lemon juice with the powdered sugar to a spreadable mixture and brush the still hot pastries with it.