In a large bowl, combine the sliced apples, brown sugar, cinnamon, nutmeg, raisins, lemon juice, and cornstarch. Toss until the apples are evenly coated. Let it sit for about 10-15 minutes.
On a lightly floured surface, roll out half of the puff pastry sheet into a rectangle about 10×12 inch. Place it on a parchment-lined baking sheet.
Visually divide the puff pastry into three vertical sections. The middle section will hold the filling
Sprinkle half of the breadcrumbs evenly over the puff pastry to absorb moisture. Then, spoon half of the apple filling down the center of the pastry, leaving 1.5 inch space on the top and bottom to seal.
On each of the two outer sections, use a sharp knife to cut horizontal slits, about 1-inch wide (2.5 cm), creating strips along both sides. These strips will be folded over the filling to form the braid. Make sure the number of strips on each side is even.
Starting at the top, fold one strip from the left side over the filling, followed by a strip from the right side, crossing them diagonally over the filling to form a braid. Continue alternating strips from each side until the entire strudel is braided
Fold the top and bottom ends of the pastry over the filling to seal them, tucking the ends under to secure.
Repeat the steps with the second half of the puff pastry sheet, making a second strudel.
Brush the braided pastries with plant-based milk for a golden finish.
Bake in the preheated oven for 25-30 minutes, or until the pastry is golden brown and flaky.
Once baked, let the strudel cool for a few minutes before slicing. Dust with powdered sugar and serve warm.
Notes
Room Temperature: Store leftover apple strudel at room temperature for up to 2 days. Cover it loosely with foil or parchment paper (as opposed to wrapping it tightly) to keep the exterior flaky.
Freezer: You can freeze apple strudel for up to 3 months. I recommend freezing it before baking, then adding a few extra minutes to the baking time. If you want to freeze leftovers, you can do that too and simply thaw at room temperature. Either way, wrap the apple strudel well and place it in an airtight container or freezer bag.