Scallion pancake, also known as cong you bing, is a popular street food in Taipei. It is made by mixing flour, water, and chopped scallions to form a dough, which is then rolled out and pan-fried until crispy and golden brown. Scallion pancake is often served with a dipping sauce made from soy sauce, vinegar, and chili oil. The crispy texture and savory flavor of the pancake make it a delicious snack or breakfast option.