Step 1: Prepare the Beef

1. In a mixing bowl, combine soy sauce, hoisin sauce, oyster sauce, sesame oil, sugar, white pepper, garlic, and ginger. Whisk until the sugar is dissolved.
2. Add the sliced beef to the marinade and toss to coat evenly. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes to let the flavors develop.

Step 2: Make the Scallion Pancake Dough

1. In a large mixing bowl, combine the all-purpose flour and salt. Slowly pour in the boiling water while stirring with a wooden spoon or chopsticks.
2. Gradually add the cold water and knead the mixture into a smooth dough. This will take about 5–7 minutes.
3. Cover the dough with a damp towel and let it rest for 30 minutes.

Step 3: Roll and Shape the Scallion Pancakes

1. Divide the dough into four equal portions. Roll out one portion into a thin circle, about 8 inches in diameter.
2. Brush the surface of the dough lightly with vegetable oil, sprinkle with chopped scallions, and roll the dough into a tight cylinder.
3. Coil the cylinder into a spiral, then flatten it gently with your hand. Roll it out again into a thin pancake. Repeat for the remaining portions.

Step 4: Cook the Scallion Pancakes

1. Heat a non-stick skillet or cast-iron pan over medium heat. Add a small amount of vegetable oil to the pan.
2. Cook each pancake for 2–3 minutes on each side, or until golden brown and crispy. Set aside on a plate lined with paper towels.

Step 5: Cook the Marinated Beef

1. Heat a large skillet or wok over high heat and add a tablespoon of vegetable oil.
2. Sear the marinated beef slices in batches, cooking for about 1–2 minutes on each side. Avoid overcrowding the pan to ensure even cooking.
3. Transfer the cooked beef to a plate and set aside.

Step 6: Assemble the Beef Rolls

1. Lay a scallion pancake flat on a clean surface. Spread a thin layer of hoisin sauce over the pancake.
2. Arrange a few slices of cooked beef down the center of the pancake. Add pickled vegetables (if using) and a handful of fresh cilantro leaves.
3. Roll the pancake tightly around the filling, tucking in the edges as you go. Slice in half and serve warm.