Shaking Beef

1 ½ to 2 pounds beef tenderloin (filet mignon), trimmed of excess fat and cut into 1-inch cubes
2 tablespoons chopped garlic
2 tablespoons sugar
Salt and pepper
5 tablespoons neutral oil, like corn or canola
¼ cup rice-wine vinegar
¼ cup rice or white wine
3 tablespoons soy sauce
1 tablespoon fish sauce
1 red onion, peeled and sliced thin
3 scallions, trimmed and cut in 1-inch lengths
2 tablespoons butter
2 bunches watercress, washed and dried, or 1 head red leaf lettuce, washed, dried and separated into leaves
2 limes, cut into wedges

Nutritional Information
- Nutritional analysis per serving (4 servings)
  812 calories; 59 grams fat; 19 grams saturated fat; 0 grams trans fat; 27 grams monounsaturated fat; 6 grams polyunsaturated fat; 26 grams carbohydrates; 2 grams dietary fiber; 8 grams sugars; 43 grams protein; 183 milligrams cholesterol; 1138 milligrams sodium

4 servings

Marinate meat with garlic, half the sugar, 1 teaspoon salt, 1/4 teaspoon pepper and 1 tablespoon oil for about 2 hours. (Refrigerate if your kitchen is very warm.) Meanwhile, combine vinegar, remaining sugar, wine, soy sauce and fish sauce. Taste, and add salt and pepper if necessary. Mix about 1 tablespoon salt and 1 teaspoon pepper in a small bowl.
Divide the meat into 2 portions, and do the same with the onion and scallions. Put a wok or a large skillet over maximum heat, and add about 2 tablespoons oil. When the oil smokes, add the meat in one layer. Let it sit until a brown crust forms, and turn to brown the other side. Browning should take less than 5 minutes. Add half the onion and half the scallions, and cook, stirring, about 30 seconds. Add about half the vinegar mixture, and shake pan to release the beef, stirring if necessary. Add half the butter, and shake pan until butter melts. Remove meat, and repeat.
Serve beef over watercress or lettuce leaves, passing salt and pepper mixture and lime wedges at the table.