Thaw the puff pastry if not already done. Preheat the oven to 400ºF (200ºC). Line a baking sheet with parchment paper.

Peel, core, and dice the apples into small cubes. In a large bowl, combine the apples, brown sugar, cinnamon, and lemon juice. Toss well, then place the mixture in a colander over the bowl and let sit for 10 minutes to drain excess liquid.

Collect the drained juices in a small saucepan. Add the butter and simmer for a couple of minutes until the mixture thickens slightly. Set aside.

On a lightly floured parchment paper, roll out the puff pastry into a 9 x 12-inch rectangle. Sprinkle the pastry with breadcrumbs to prevent sogginess.

Toss the raisins with the prepared apple cubes. And spread evenly over half of the pastry (lengthwise) leaving a 1-inch border on all sides. Carefully roll the pastry up from the long side, using the parchment paper to help you. Form a log, seam side down, and tuck the ends under to seal the filling. Use egg wash (egg beaten with milk) to seal the edges. Using a sharp knife, make a few small slits on top of the strudel to allow steam to escape. Brush the top with the egg wash.

Place the strudel on the prepared baking sheet and bake for 25-30 minutes, or until the pastry is golden brown.

Allow the strudel to cool slightly, then dust with powdered sugar. Slice into portions and serve warm or at room temperature. Optional: Pair with vanilla sauce, a scoop of ice cream, or whipped cream for an extra treat.