Place the apple wedges in a large bowl. Drizzle with lemon juice and toss to coat.

Heat the rum, if using, to a simmer. Place the raisins in a bowl and cover with the hot rum. Set aside.

Melt the 6 tablespoons of butter in a large, lidded pot. Add the apples with juices, sugar, cinnamon, and lemon zest. Cover the pot and allow to cook 12 minutes, then uncover and cook an additional 10-15 minutes until the liquid evaporates. Fold in the rum-soaked (or not) raisins into the apple mixture, then spread the filling out onto a sheet pan to cool.

In the bowl of a mixer fitted with a paddle, combine the flour and salt. Whisk together the eggs and oil in a medium bowl. Pour the eggs and oil into a measuring cup and while whisking, add enough milk to reach the 1 ¼ cup line. With the mixer on low, pour the egg and milk mixture into the bowl with the flour. Mix until a shaggy dough comes together, then remove the paddle and switch to a dough hook. Knead until a smooth, elastic dough forms, about 2 minutes. Turn off the machine, form the dough into a ball, and turn it into a lightly oiled bowl. Let it sit at room temperature for at least 1 hour, and up to 2.

Preheat oven to 400˚F. Melt the remaining cup of butter in a small saucepan.

Cover a large table with a clean sheet and dust it liberally with flour, rubbing the flour into the sheet where you’ll roll out the dough. Remove the dough from the bowl and use a paper towel to wipe off any excess oil. Place on the floured surface and dust with more flour. Use a rolling pin to roll it out to a 24-inch square. Brush the dough with melted butter, all the way to the edges. Gently tug the dough gently around the edges, very gently stretching it out. Use the palms of your hands to reach further underneath the dough to stretch out the center. If it starts to tear, move to a different area (don’t worry about small tears). You’ll want the dough to be thin enough to be able to see a printed page through it. When you’re ready to add the filling, trim of the outside edge with scissors or a sharp knife. Brush the sheet with butter again. Sprinkle the breadcrumbs onto the pastry near one edge in a long stripe, as wide or as narrow as you like. Top the breadcrumbs with the chopped nuts, then with the apple raisin filling.

Bring the edge of the sheet up and use the sheet to flip the edge of the dough over onto the filling. Gather up the sheet behind the strudel and repeat, over and over, until it’s all rolled up. Leaving about 2 inches on each end, trim the ends of any spare dough. Tuck the excess dough underneath the strudel. Transfer the strudel to a sheet pan, seam-side-down. You can bend the strudel, making a “U” or an “S” to make it fit the pan (if needed, you can use two pans side by side, but you’ll need help getting them in and out of the oven. Brush with more melted butter. Allow to rest for 15 minutes, then transfer to the oven and bake for 40 minutes until dark golden brown. Allow to cool completely. Dust with powdered sugar, and slice and serve.