Heat the milk 40 degrees and mix the sugar together with the yeast
into the milk. Wait 5 to 10 minutes until it gets foamy.
Melt the butter and combine the flour, salt, vanilla, 3 egg yolks
with the butter and the yeast-milk mixture.
Knead until you have a smooth dough, by hand roughly 15 minutes, by
machine 5.
Give the dough one hour to grow. After 30 minutes fold it once. In
the mean time cut the chocolate into small pieces.
Knead the chocolate into the dough. This should be done by hand,
since a machine spreads the chocolate to evenly, which results in a dark
brown dough, instead of chocolate spots.
Cut 10 to 12 pieces and form them into small balls. Roll each ball
in the leftover egg yolk and put on a oven tray. Let it rest for 10 more
minutes.
