Ingredients

• 1 1/2 tablespoons fresh lime juice
• 1 tablespoon fish sauce
• 1 tablespoon sugar
• 2 Thai bird chiles or 1/2 serrano chile, chopped
• 1 tablespoon oyster sauce
• 2 teaspoons soy sauce
• 2/3 pound beef sirloin or flank steak, cut into 1/2-inch cubes
• 2 to 3 tablespoons vegetable oil
• 2 cloves garlic, sliced
• 1/4 ripe pineapple (about 1/2 cup), cut into bite-sized slices about 1/4-inch thick (optional)
• 1/2 cup Asian basil leaves, cut in half
• 1/4 red onion, thinly sliced lengthwise
• 3 cups watercress, washed, picked over, and torn into bite-sized sprigs
• 1 ripe tomato, cut into thin wedges

Instructions

1. Combine the lime juice, fish sauce, sugar and chiles in a large bowl. Set aside.
2. Place the oyster sauce, soy sauce and beef in a medium bowl and toss to coat the meat evenly.
3. Heat the oil in a large skillet over high heat. Add the garlic and stir until fragrant, about 5 seconds. Add the beef and quickly stir-fry it until just charred on the edges, about 2 to 3 minutes. Add to the bowl with the lime sauce.
4. Add the pineapple slices, if using, Asian basil and red onion to the beef mixture. Spread the watercress and tomatoes in an attractive manner on a serving platter. Arrange the beef mixture and all its juices on the watercress and serve immediately (if desired, with a warm baguette or steamed rice to soak up the juices).