In a large bowl, combine the flour and salt. Create a well in the center and add the oil and warm water. Mix until a shaggy dough forms.

Knead gently for about 5-7 minutes until smooth. Cover with a damp cloth and let it rest for at least 30 minutes.

While the dough rests, preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper.

In a bowl, combine the sliced apples, sugar, cinnamon, nutmeg, raisins or walnuts (if using), and lemon juice. Toss until the apples are well coated.

On a clean, floured surface, roll out the dough as thinly as possible, ideally stretching it out with your hands for an even thinner base. The dough should be translucent in places.

Brush the rolled-out dough with melted butter. Spread the apple filling evenly over the surface, leaving a small border around the edges.

Carefully roll the dough, starting from one of the short sides, to form a log. Seal the edges by pinching them to prevent any filling from leaking out.

Place the rolled strudel seam-side down on the prepared baking sheet. Brush the top with melted butter for a crispy, golden crust.

Bake in the preheated oven for 30-40 minutes until golden brown. Check for doneness by looking for a crisp, deep color on the exterior.

Let it cool for a few minutes before slicing. Serve warm with a dusting of powdered sugar or a scoop of vanilla ice cream on the side.