Combine quark, egg, butter, flour, salt, vanilla sugar and zest knead to form a smooth dough. Wrap in foil and chill for 1 hour. Rinse apricots, pat dry, cut lengthwise and remove core from each side. Place a sugar cube in place of the core.
Divide dough into 8 portions. Roll out to form circles about 3-4 mm (approximately 1/10 inch) thick and 10 cm (approximately 4 inches) in diameter. Place an apricot on each circle and wrap around. Pinch seams with wet fingers to seal.
Boil dumplings in lightly salted water for about 10-15 minutes. Remove with a slotted spoon and drain.
In the meantime, beat cream cheese, lemon juice and jelly until smooth. Grind poppy seeds. Brown butter in a pan and add poppy seeds. remove from heat and set aside. Pour cream cheese sauce onto 4 plates, top with dumplings and serve garnished with poppy butter and mint.