Dissolve yeast in warmed milk (approx. 1/3 of the total amount indicated) and mix with a little flour to form a thick dampfl and leave to rise in a warm place.
Heat the remaining ingredients, milk, butter, egg yolks, sugar, vanilla sugar, lemon zest, rum and salt and knead with the dampfl and flour to a smooth dough.
Cover and let rest for 20 minutes.
Then roll out the dough into a rectangle (about 5 mm thick). Brush with melted butter and sprinkle with cinnamon, sugar and raisins.
Roll up the covered dough and place it in a buttered baking pan. Let the dough rise again.
Bake at 160 °C for about 50-60 minutes.
Remove from the oven and turn out.