Mix the yeast with lukewarm milk, stir in 100 g flour and let rest in a warm place.
Beat egg, granulated sugar, vanilla sugar, salt, lemon juice and rum until fluffy.
Melt butter and stir into egg mixture.
Combine germ mixture with remaining flour and egg mixture in a mixing bowl until smooth and let rest again for 30 minutes.
Then roll out the dough, cut out rounds, fill with apricot jam and close the dough circles tightly.
Dip in warm butter and place in a greased pan.
Let rise again and bake at 160 – 170 °C for about 25 – 30 minutes.