For the curd strudel, knead flour, salt, oil, vinegar, yolks and water into a strudel dough. Let the dough rest for 1 hour.
For the curd filling, beat the yolks, powdered sugar and vanilla sugar until foamy. Mix the curd, yolk mixture, lemon juice, salt, cornflour and melted butter with a wooden spoon (do not use a mixer or the curd will lose its stability during baking).
Divide the strudel dough into 2 parts. Dust the strudel cloth with flour, roll out the dough and then roll it out thinly.
Cut away the edges, spread with half of the curd filling and spread the strawberries on top, fold in and roll up.
Place on a baking tray lined with baking paper. Fill the 2nd strudel dough in the same way. Brush with melted butter and bake at 180 degrees for about 45 minutes.
The curd strudel can be served warm or cold. Sprinkle with powdered sugar before serving.