If you decide to use raisins, soak them in water for at least 15 minutes. If you prefer to use chocolate, cut it into small cubes.

Meanwhile, melt the butter in a pan, pour in the breadcrumbs and brown them for a couple of minutes on high heat, stirring often.

Roast the pine or sunflower seeds briefly in another pan as well.

Peel the apples, cut them into four parts, remove the peel and cut into thin slices. Transfer the slices to a bowl, and add the grated lemon zest and lemon juice.

Add pine or sunflower seeds, soaked and drained raisins or dark chocolate, brown sugar and cinnamon. Mix well.

If your puff pastry is sold in thick rectangles, flatten the sheets with a rolling pin to double its size.

Gently sprinkle the breadcrumbs on the bottom layer, leaving an inch free from the edges. Pour the apples evenly over the four puff pastry sheets or on half of each big sheet and seal them with the remaining four sheets or the other half of the sheet.

Fold the side edges and seal them well by moistening with water to allow them to adhere and prevent the mixture from leaking.

Beat the yolk and brush the surfaces. Make an incision on the surface of the strudel.

Bake in a ventilated oven at 180 ° for about 25 minutes at the bottom of the oven. Take the strudel out of the oven, allow to cool and then sprinkle the surface with icing sugar to taste.