Peel and quarter the apples and cut out the cores. Cut apples into pieces and put them in a pot with 75 grams of sugar and lemon juice. Steam at low heat for 12 to 15 minutes and let cool down.
In the meantime, mix the quark, oil, egg liqueur, remaining sugar, vanillin sugar and salt with the whisk of the hand mixer. Mix flour and baking powder with the dough hooks of the hand mixer.
Finally, work into a smooth dough with your hands. Roll out to a thickness of about 1/2 centimetre on a lightly floured work surface and cut out twelve circles using a round cookie cutter (12 cm Ø).
Place two teaspoons of stewed apples on each half of the dough. Moisten the edges of the dough with water and fold over the other half of the dough. Press the edges together slightly and roll out with a small wheel.
Place on two baking trays lined with baking paper and bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for 15 minutes one after the other. Let them cool down on a cake rack. Stir icing sugar and apple juice until smooth.
Pour into a freezer bag and cut off a small corner. Decorate apple pockets with strips of icing. Sprinkle some apple pockets with pistachios if you like. Let it dry. Arrange the apple pockets on a plate and serve decorated with lemon balm as desired.