In the bowl of an electric mixer fitted with a dough hook, mix the flour and salt on low speed to combine., In a container with a spout, whisk the water, egg yolks, oil, and vinegar to combine. With the mixer running, add the liquid to the mixer in a slow, steady stream., Mix on low speed for 10 minutes. At this point, the dough should have formed a ball around the dough hook, and should appear relatively smooth. It should be slightly tacky (not sticky) but not dry — if it seems dry, add more water 1 tablespoon at a time, mixing for a full minute before checking the texture., Raise the mixer speed to medium and continue to mix for 10 minutes more. Transfer the dough to a medium-sized oiled bowl and turn the dough over a few times to coat it lightly with oil. Cover with plastic wrap and refrigerate overnight. The finished, rested dough is now ready to be stretched and filled., Line a tabletop with a tablecloth; oilcloth or linen work especially well. A folding card table, kitchen table, or any surface you can walk all the way around will work; it will make the stretching easier., Remove the strudel dough from the refrigerator. Lightly oil your hands. The dough should feel lightly tacky but not sticky, and it should stretch easily. Start by stretching the dough a little like a pizza, trying to keep it rectangular as you work. Once the dough is no longer easy to manage with your hands, lay it down on the covered table., Use closed fists to stretch the dough. Put your hands under the dough at one corner, and gently work your fists outwards, working toward the edge of the table. Continue to do this, bit by bit, working around the dough to slowly stretch it out. The goal is to get it so thin you can see through it (if your tablecloth has a pattern, this can be a good guideline). Don't be alarmed if the dough tears (you'll be rolling it up, and the tears will get rolled up and hidden inside). The dough is very strong, and you should be able to stretch it without major tearing., Once the dough is stretched to the edge of the table, use your fingers to pull gently around the edges to make sure they aren't too thick., To assemble the strudel: Drizzle the strudel with butter (don't brush it on; you may tear the dough) and top with bread crumbs, as directed in your choice of the recipes listed in "tips," below. Spread with filling., Working with one of the shorter sides, gently grab the dough and roll it up into a tight spiral. Use the tablecloth to help you — the less you handle the dough, the less likely you are to rip it., Use scissors to cut any excess dough away from the ends of the strudel, and discard., Lift up the rolled strudel, seam side down, and place it diagonally onto a 13" x 18" half-sheet pan. If it's too long to fit, you can form it into a horseshoe shape instead. Finish and bake according to each recipe's specific directions.