Scallion cake is a special snack of Han nationality in Shanghai, which belongs to Shanghai cuisine. This kind of snack is bright yellow, decorated with scallion oil, crispy outside and crispy inside, and it is ready to eat and cook. Speaking of scallion cakes, they should be found all over the country, but each place has its own characteristics, and the practices are not exactly the same, big and small. The scallion cake in old Shanghai is basically about 10 cm in diameter, and its thickness must reach 1 cm upward.