Make the dough: in a bowl combine All-Purpose Flour with a pinch of Salt. Stir in lukewarm Water, Neutral Oil and a splash of Apple Cider Vinegar until a sticky dough forms, then turn out and knead until smooth and elastic (about 8–10 minutes). Form into a ball, coat lightly with oil, cover and let rest at room temperature for 30–60 minutes to relax the gluten.
Soak the raisins: place the Raisins in a small bowl and pour over the Dark Rum (or just hot water if you prefer). Allow them to plump for 15–20 minutes, then drain, reserving any soaking liquid if you like to add a little extra moisture to the filling.
Prepare the apple filling: core and thinly slice the Tart Apples. In a large mixing bowl toss the apple slices with Granulated Sugar, Vanilla Sugar, Ground Cinnamon, grated Lemon Zest and a little Lemon Juice to brighten the flavors. Fold in the soaked Raisins.
Toast the crumbs: melt half of the Unsalted Butter in a skillet over medium heat, add the Breadcrumbs and a couple of tablespoons of Granulated Sugar, and toast, stirring, until the crumbs are golden and fragrant. Remove from heat and let cool slightly—these will soak up excess juice and add a toasty texture to the strudel.
Roll and stretch the dough: on a lightly floured surface (use extra All-Purpose Flour as needed) roll the rested dough into a thin rectangle, then carefully stretch it with your hands or a rolling pin until nearly translucent—traditional strudel dough is very thin. Transfer the dough to a clean tea towel or parchment for easier rolling.
Assemble: brush the entire surface of the stretched dough with the remaining melted Unsalted Butter. Sprinkle the toasted Breadcrumbs in a thin, even layer over the buttered dough, leaving a few inches clear along one long edge. Spread the apple–raisin mixture in a long strip along the breadcrumb layer, keeping the filling compact so rolling is easier.
Roll up the strudel: using the towel or parchment to help, gently fold the short ends over the filling and roll from the filled edge to enclose it, creating a tight log with the seam on the bottom. Transfer the strudel to a baking sheet lined with parchment, seam side down. Brush the top with more melted Unsalted Butter.
Bake: preheat the oven to 190°C (375°F). Bake the strudel for 35–45 minutes, rotating halfway, until the pastry is deep golden brown and the filling is bubbling in places. If the top browns too quickly, tent loosely with foil.
Finish and serve: let the strudel rest 10–15 minutes to set, then dust generously with Powdered Sugar before slicing. Serve warm, optionally with whipped cream or vanilla ice cream.
