Rinse sultanas and pat dry. For the filling, wash the lemon hot, grate dry, grate the peel thinly. Halve the fruit and squeeze the juice. Peel, quarter, core and dice the apples.
Caramelise 50 g sugar in a pot until light yellow. Add apple cubes, sultanas, lemon peel and 3 tbsp. lemon juice and simmer for about 4 minutes while stirring. For the dough mix flour and baking powder.
Knead butter, quark, oil, 5 tablespoons of milk, 100 g sugar and flour mixture with the dough hooks of the hand mixer to a smooth dough. Roll out the dough on the floured work surface approx. 3 mm thin. Cut out 30 circles (approx. 8 cm Ø).
Spread apple compote over the circles. Spread the edges of the dough thinly with the remaining milk and fold over the dough. Press the edges of the dough lightly. Spread on two baking trays lined with baking paper and bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) one after the other for about 20 minutes each.
Stir icing sugar, 1 tablespoon lemon juice and 1 tablespoon water to a smooth glaze. Take apple pockets out of the oven and spread a thin layer of prepared icing.