Knead the dough ingredients into a yeast dough and let rise for 60 minutes.
In the meantime, use the pudding powder, milk and sugar to cook a thick pudding. Stir the sour cream into the still hot pudding and let it cool down.
Knead the yeast dough again briefly and roll out about 1.5 cm thick. Spread the pudding on the longer half. Slightly cut into the other half and roll up. Place on a baking tray lined with baking paper. Whisk the egg with the milk, brush the plait with it and sprinkle sugar on top. Bake in the preheated oven at 175 ° C for 25-30 minutes.