Knead the flour with a pinch of salt, 10g sugar, 50g soft cut butter, the egg and a drop of warm water. Work the dough until smooth and elastic. Allow to rest in a warm place for at least 30 minutes.
Peel and slice the apples, melt 50g butter and fry the breadcrumbs. Soak the raisins in water for 10 minutes and grate the lemon zest.
Roll out the dough with a rolling pin on a floured tea towel. Gently stretch the dough and work it with your hands, using your fists to spread it in all directions into a broad sheet, which should be almost transparent. Brush the pastry sheet with 50g melted butter and place on top the fried breadcrumbs, apple slices, raisins, pine nuts, lemon zest, remaining sugar, a pinch of cinnamon and a few small knobs of butter.
Fold the edges of the dough onto the filling, in order to contain it. Roll the strudel with the help of a tea towel, laying it on a greased plate covered with baking paper. Brush with the whisked egg yolk and bake in the oven at 190°C for approximately one hour. Serve warm or cold, dusted with icing sugar to taste.