Peony bark is probably the deepest snack in many post-80s childhood memories. It is a round little roll, sweet and sour, and very appetizing. In fact, the history of Mudan Cortex is very long. It is a famous traditional snack in northern China. It is made of hawthorn, apples, mangoes and other fruits.

According to legend, in the thirty-sixth year of Kangxi, Gao Shiqi, a court writer in the Qing Dynasty, wrote a seven-character poem called "Guo Zi Dan" on his way to Ningxia Dushi with Kangxi, saying, "It's red, penetrating, oily, thin, creamy, light and waxy. When the grass strikes, the military books are still gone, and the mouth is exhausted. " And note: "Hawthorn, boiled pulp for it, as thin as paper, even and clean, can be rolled comfortably." The color is red, so it is named Guo Dan. Sweet and sour, quenching thirst. " It can be seen from the poem that "Guo Dan" is the "Guo Dan Pi" nowadays.