Mix and knead the dough. Combine the flour and dough salt. Gradually add the lukewarm dough water, then knead for 8–10 minutes. After about 5 minutes, work in the oil listed for kneading. The dough should become soft, smooth, and elastic.
Divide and rest. Divide into balls weighing about 14½ oz (410–415 g) each, keeping the same ball size when scaling. Coat with the oil listed for coating, cover, and rest at room temperature for 45 minutes.
Mix the cold filling. Finely dice the onions to about ⅛ inch (2–3 mm). Gently mix with the raw ground beef, filling salt, pepper, and cold filling water just until combined. Do not knead it into a paste. Cover and refrigerate at 40°F (4°C) or colder until shaping. Clean hands, utensils, and surfaces after handling raw beef.
Roll and relax again. On a clean cotton-covered table, roll each ball into a round about 12 inches (30 cm) across. Lightly oil the rounds using a little of the stretching oil, cover, and rest for 15 minutes. Preheat the oven to 390°F (200°C), conventional heat, or 355°F (180°C) with convection. Grease shallow metal pans with the pan oil.
Stretch the jufka. Work with one round at a time, keeping the others covered. Slide the backs of your hands under the dough and stretch gently from the center outward until almost transparent and about 35–39 inches (90–100 cm) across. Trim the thick outer rim. Small edge tears are manageable; avoid large holes where the filling will sit.
Fill and roll loosely. Reserve about one fifth of the stretching-and-brushing oil for the final surface. Distribute the remainder across the stretched sheets, including the oil already used on the rounds. Divide the chilled filling evenly among the dough pieces, placing a loose, narrow line along one side of each sheet. Leave about 2 inches (5 cm) clear at each end. Fold in the ends, then lift the cloth to roll the dough loosely around the filling.
Coil without crowding. Loosely coil the first roll in the center of a greased round metal pan about 12½–13 inches (32 cm) across. Arrange another roll around it without compressing the pastry. At larger recipe scales, use additional pans and repeat; do not build a deeper pie. Brush with the reserved surface oil.
Bake and check the center. Bake on a lower-middle rack for about 40–45 minutes, checking the browning after 30 minutes. If needed, shield the top loosely with foil. Check the beef filling in thick sections with a thermometer: it must reach at least 160°F (71°C). Continue baking if the filling is not hot enough or the bottom remains pale; allow an extra 5–10 minutes as needed.
Rest and serve. Rest in the pan for 10 minutes, then cut into portions and serve warm. Leave uncovered during the short rest to keep the crust crisper. Yogurt is a customary accompaniment.
Chill leftovers promptly. Divide leftovers into shallow portions and refrigerate within 2 hours, or within 1 hour above 90°F (32°C). Keep at 40°F (4°C) or colder and use within 2–3 days. Reheat in a 340°F (170°C) oven until the center reaches 165°F (74°C). For longer storage, freeze promptly chilled portions and thaw in the refrigerator before reheating.