Stir-Fried Romaine Lettuce

Name: Stir-Fried Romaine Lettuce (Qing Chao Sheng Cai 清炒生菜)
Cuisine: Chinese
Ingredients: 1 heart of romaine or cos lettuce (about 250 g); 1 heart of romaine or cos lettuce (about 250 g); 3 tbsp cooking oil; Salt