Imagawa-yaki, also known as wheel cake, large drum cake, or red bean cake, is referred to as "guan zai guo" in Taiwanese. It is a type of wagashi, originating from the Edo period during the An'ei era at "Imagawa Bridge" in Kanda, Edo, which is how it got its name.
The outer skin of the wheel cake is made from flour, eggs, and sugar, with a filling in between the skins. Early fillings were usually made of red bean paste or a white filling made from peeled and mashed green beans.
In Japan, the Imagawa-yaki sold on the streets is primarily filled with traditional sweet fillings such as red bean paste, white bean paste, soybean paste (edamame paste), and custard cream. In recent years, many new flavors have emerged, including chocolate, matcha, taro, peanut, sesame, sweet potato, and cheese.
#Thanks to the information from Wikipedia.