Roll out the finished puff pastry.
Peel apples, cut into slices, mix with lemon juice, sugar, cinnamon and rum.
Add raisins if desired.
Lightly fry the breadcrumbs in hot butter and put them on the puff pastry.
Brush the edges of the pastry with egg. Spread apple filling on top and roll up dough.
Press the edges on the top and sides. Brush strudel with egg and bake at 190 °C until golden brown.