Roast the oat flakes in a pan without fat, remove from the pan and allow to cool. Stir in curd, soured milk, sugar and vanillin sugar. Put 1 teaspoon of currant jam aside, stir the remaining jam into the quark. Arrange dessert in portioned bowls. Place a blob of the remaining jam on each, sprinkle with oat flakes and serve decorated with lemon balm leaves as desired