Huanglong mung bean cake. The mung bean cake in Hai Duong Province, Vietnam is the most famous among the many varieties of mung bean cake in Vietnam. Haiyang Huanglong Company in Vietnam is the most famous ancient mung bean cake production base in Vietnam. Its most popular products among consumers are Huanglong mung bean cake and Yulong mung bean cake. Instead of using traditional cooking methods, Huanglong Mung Bean Cake is more authentic and deeply loved by consumers.