Blend flour, cornstarch, 2 T sugar, & water. Set aside.
In a small bowl, stir remaining 1/4 C sugar, salt, mirin, cinnamon, and soy
sauce into mashed yams.
Spread the yam paste out onto flat pan about 1/2" thick. Refrigerate 2
hours until firm. Preheat oven to 325F.
Form into cakes by rolling paste into a small ball with your hands, then press
flat. (Wet hands to keep from sticking) Dip each cake into flour mixture &
lay on greased cookie sheet. Bake 30 minutes.