For the curd strudel tart with plums, sift flour onto the work surface, make a well in the center, add salt, sugar, egg, oil and mineral water as needed and work everything into a smooth strudel dough.
Cover the dough and let it rest at room temperature for 30 minutes. Sugar pitted plums, stew briefly in water or white wine, then drain.
For the filling, soak rolls or white bread in milk, squeeze very well and strain or mix well with a fork. Beat egg and yolk with sugar and vanilla sugar until foamy, stir in curd cheese and lemon zest. Mix in the bread mixture.
For the cream glaze, melt butter, heat with sour cream, cream and sugar and mix well, do not boil. Roll out or stretch strudel dough to a size of about 60 x 60 cm, place on a floured cloth or foil.
Spread curd mixture on the bottom half of the dough, leaving edges free. Place drained plums in two strips from left to right, spacing them slightly, on top of curd filling. Fold in the side edges, then roll up the strudel from the covered side with the help of the cloth or foil. Place it like a snail on the greased bottom of a cake pan, close the edge around it. Bake on the lowest rack at 180 degrees for about 25 minutes, then pour cream glaze over it and finish baking in about 25 minutes.
If the curd strudel cake with plums is browning too much, cover with baking paper at the end of the baking time.