Vietnamese Shaking Beef

Instructions

1. Marinate the beef
   In a large bowl, combine the beef cubes with minced garlic, oyster sauce, soy sauce, fish sauce, sugar, and black pepper. Mix well to coat the beef evenly. Cover and refrigerate for at least 20 minutes or up to 2 hours.
2. Prepare the salad base
   Arrange the watercress on a large serving platter. Place sliced tomatoes around the edges of the platter. This will be the bed for your stir-fried beef.
3. Heat the wok
   Heat a wok or large skillet over high heat until very hot. Add 2 tablespoons of vegetable oil and wait until it's smoking hot.
4. Cook the beef
   Working in batches to avoid overcrowding, add half the marinated beef in a single layer. Let it sear undisturbed for about 1 minute until nicely browned. Shake the wok vigorously (this is where the name 'shaking beef' comes from) and stir-fry for another 1-2 minutes until beef is medium-rare. Transfer to a plate and repeat with remaining oil and beef.
5. Sauté the onions
   In the same wok, add the sliced red onions and stir-fry for about 30 seconds until slightly softened but still crisp.
6. Finish the dish
   Return all the beef to the wok, add the butter, and toss everything together until the butter is melted and coats the beef. The entire cooking process for the beef should be quick, about 5 minutes total, to keep it tender.
7. Plate and serve
   Immediately transfer the hot beef and onion mixture to the prepared watercress and tomato platter. The heat from the beef will slightly wilt the watercress. Serve with lime wedges and steamed white rice on the side.