There are 4 parts to this dish:
Beef:
Vinaigrette:
Salad:
For Dipping:
Beef:
In a large bowl, combine the beef, garlic, oyster sauce, dark soy, fish sauce, brown sugar, and black pepper. Toss to combine. Let marinate at room temperature for 30 minutes.
Preheat a large wok or cast-iron skillet over high heat, then add the oil. When the oil is shimmering, swirl the oil around and working in batches, add half the beef, searing on all sides. Shake and move the pan on all sides until the meat is slightly charred and medium-rare, 3-5 minutes. (Feel free to use tongs to turn and arrange beef as necessary.) Set the meat aside on a plate, tented to keep warm, and repeat with remaining beef.
Vinaigrette:
In a small bowl, mix together the rice vinegar, sugar, soy sauce, water, black pepper, and salt. Add red onion and set aside to marinate.
Salad:
Place the watercress or lettuce on a platter, leaving space for the beef to be piled in the center. Arrange the cucumbers and tomatoes around the outside edges. Strew the red onion from the vinaigrette across the top of the beef and use a spoon to distribute some of the vinaigrette over the beef and on the salad ingredients. Pass the rest of the vinaigrette.
For Dipping:
Divide the salt and pepper into 4 small dishes or serving spoons. Garnish with a wedge or two of lime.
To Finish/Serve:
Garnish with cilantro if desired. Serve with white rice.
Find it online: https://frugalhausfrau.com/2019/05/13/shaking-beef-bo-luc-lac/