Melt butter. Put flour into a bowl. Make a dint in the middle. Heat up milk until lukewarm. Crumble yeast in the dint and add one tea spoon of sugar. Add milk and mix with a little flour to a pre-dough. Cover and let go in a warm place for approximately 15 minutes.
Give remaining sugar, vanilla sugar, butter, egg and low-fat curd to the flour and stir with a dough hook until smooth. Put one quarter of the dough aside. Mix blueberries and almonds and stir in the extra dough. Cover both dough and let go approximately for 45 minutes.
Put baking paper on baking tray. Divide the yeast dough (without blueberries) into 12 portions. Roll each portion in floured hands to a ball and flatten gently. Similarly divide blueberry yeast dough into 12 portions. Place one of the blueberry yeast dough portions each on the flattened yeast dough and close the dough around it and press together. Form to a ball one more time. Place bread buns with a little distance between them on a baking tray. Let go an additional 10-15 minutes.
Carve the dough slightly with a knife. Mix condensed milk and milk and brush on dough. Dredge with sugar crystals. Bake in preheated oven at 180 F or 82 C for approximately 18-20 minutes.