1Sift the flour onto the work surface and add the water, oil, 1 whole egg, and a pinch of salt. Mix well.
2Work the dough vigorously with both hands until it is smooth and elastic.
3Shape the dough into a ball, brush it with oil and set it aside to rest for 30 minutes.
4Add the butter, sugar, lemon zest, baking powder, vanilla extract and 5 egg yolks to a bowl and mix well.
5Add 5 egg whites to a bowl and whisk until stiff peaks form.
6Add the cheese, the rolls which have been soaked in milk and put through a food mill, the sour cream and the stiffly beaten egg whites.
7Preheat oven to 180 degrees Celsius.
8Roll out the dough with a rolling pin directly on a floured work surface.
9Pull at the dough to stretch it to a paper thin sheet, carefully so it does not tear.
10Spread the filling on the dough and sprinkle it with the raisins. Cut off the uneven edges of the dough and, roll up the dough tightly.
11Place the strudel on a buttered baking sheet and shape it into a crescent.
12Brush the strudel with melted butter and bake it at medium heat for approximately 40 minutes total baking time, after 20 minutes pour some milk onto the strudel and finish baking.