Let the butter come to room temperature and beat it along with half of the sugar, salt lemon zest, and vanilla sugar (to taste) until fluffy. Next, gradually add the egg yolks, still beating to maintain a fluffy consistency then fold in the brad (cubed and soaked in milk), sour cream, breadcrumbs, and raisins. Finally, beat the egg whites together with the remaining sugar and carefully fold into the mixture.

For the egg milk, mix together milk, egg, and sugar.

For the Strudel dough, place all the ingredients in a food processor and blend them to make a smooth dough. (The amount of water needed depends on how much water the flour can absorb, the may require some experimentation.) As soon as the dough has reached the proper elastic consistency, form it into a ball brush the ball with oil, and let it rest for at least 30 minutes.

Once the Strudel dough has rested, roll it out a bit with a rolling pin to foam a circular shape. Then place dough on a cloth dusted with flour, carefully lift it with the backs of both hands, and gradually pull it out to all sides until the pulled-out dough surface extends several centimetres over the edge of your work surface. Spread the filling onto two thirds of the dough. Carefully brush the rest of the dough’s surface with melted butter. Roll up the strudel and place in a greased pan. Pour in halt of the egg milk. Bake in the oven for ca. 30 minutes at 180°C using upper and lower heat. Afterwards, pour on the rest of the egg and bake the strudel for another 15 to 20 minutes, at which point it should be a nice golden yellow colour.

Vanilla sauce goes well with this dessert.