In a small frying pan heat the butter and fry the bread crumbs until golden brown. This will add extra flavour to the mixture. Mix into the apple filling.
2 tablespoon butter, 5 tablespoon bread crumbs
Roll out the puff pastry into a rectangle on a piece of baking parchment. Mine was 40 x 20 cm. Place the strudel filling lenghtwise onto the dough in a strand that has equal height and width.
11 oz puff pastry
Mix the egg into a smooth egg wash. Brush the edges of the puff pastry with it and then fold the sides over the mixture. Fold over the shorter edges so no filling can escape when it is cooking.
Place the strudel - seam side down on a baking tray lined with baking parchment. I find it easier to lift the strudel on the baking parchment that it was rolled on and then putting it upside down on another sheet. This reduces the danger that the strudel may rip.
Brush the top of the strudel with the remaining egg wash. With a sharp knife made a few incisions on the surface. This will allow the hot air to escape and the pastry to bake nice and fluffy. Bake in the oven for approximatley 25 minutes.
While the strudel is baking you can prepare the vanilla sauce if desired. Find an easy recipe here.
Serve the strudel lukewarm with vanilla sauce, whipped cream or vanilla ice cream.