In a bowl, combine the flour, salt, oil, and then add the water, a little at a time. Mix until the dough is smooth and elastic. Place it in a lightly oiled bowl and let stand for 30 minutes.
Soak the raisins in the rum with the same quantity of water. Peel, core, and dice the apples. In a bowl combine the apples with the sugar, the raisins, the rum, and the melted butter. Cover the bowl with plastic wrap and set it aside in the fridge.
On a pastry board lay down a kitchen towel, sprinkle with flour, and roll the dough as thin as 1/8 inch (2-3mm).
Sprinkle the dough with breadcrumbs or a few crumbled biscuits in order to soak up the liquid from the apples.
Pile the apple filling on the breadcrumbs.
Then roll up the strudel with the help of the towel.
Seal the edges with a little beaten egg.
Transfer the strudel to a baking sheet lined with parchment paper, brush with some beaten egg, and dust with a mix of sugar and cinnamon. Make some diagonal incisions on the top to let the steam escape. Brush the top with a little melted butter.
Pre-heat the oven to 350°F (180°C) and bake for 40 minutes. Have the strudel either warm or cold.