Mix flour, baking powder, 125 g sugar and salt in a bowl. Add 1 egg and 125 g butter in flakes. Knead first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Wrap in foil and chill for approx. 45 minutes
Melt 2 tablespoons of butter in a frying pan. Brown the breadcrumbs and pine nuts in it. Remove from heat and let cool off. Peel apples, cut into eighths and remove seeds. Cut apples into fine slices. Mix with 2 tbsp. sugar, crumb mixture, vanilla sugar, lemon peel and lemon juice. Roll out dough on a floured work surface in a rectangular shape (approx. 26 x 37 cm). Pour the apple mixture onto the dough, leaving about 2 cm of edge free. Whip short, lateral edges over the filling, then roll up from the long side
Place the strudel on a baking tray lined with baking paper. Whisk 1 egg and brush the strudel with it. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 25-30 minutes. Let cool on a cake rack. Dust with icing sugar if necessary. Whipped cream tastes good with it
Waiting time approx. 30 minutes