Preheat oven to 350 °F (180 °C).

Prepare the strudel dough according to the basic recipe.

For the filling, heat butter in a pan and lightly brown some of the breadcrumbs in it.

Peel, quarter, and core the apple and cut them into thin slices.

Mix with raisins, the rest of the breadcrumbs, sugar, vanilla sugar, cinnamon, lemon zest, and rum.

Lay a cloth on the work surface and flour evenly.

Lightly flour the dough as well and place on the cloth.

With a rolling pin, roll the dough out as thinly as possible.

Then slide both hands under the dough, palms down, and slowly stretch it in all directions, until it’s so thin that you could read a newspaper through it.

Be very careful not to tear the dough.

Saturate the dough with ¾ of the melted butter.

Lay the filling on the dough in a strip.

With the help of the cloth, fold the dough over the filling and then fold around once.

Cut off extra.

Place the strudel with the seam down on a buttered baking sheet and brush with the rest of the butter.

Bake for about 40 minutes.

Dust with confectioner’s sugar and serve while still warm.