The recipe I used (sorry, I don't know the source - it was sent to me ages ago and I'm only now trying it!):
Onimanju (Devil's Cake)
3/4 lb satsumaimo (sweet potato, preferably the Japanese variety), cut into about 1/2 inch cubes
1/2 cup sugar
1 cup flour (I used half whole wheat and half all-purpose)
1 Tbsp shiratamako flour (I used sweet or glutinous rice flour [mochiko])
2 Tbsp milk
Soak satsumaimo cubes in water for about 15 minutes and drain (to draw out the starchiness, perhaps?).
Place satsumaimo cubes in a large bowl and sprinkle sugar over them. Set aside for about 30 minutes so that some liquid gather at the bottom of the bowl. Drain the satsumaimo cubes and keep the liquid in another bowl. Add mixture of flour and shiratamako in the liquid and mix. Add milk to the dough. If the dough is too thick to stir, add a little bit of water. Mix in satsumaimo cubes.
Scoop a spoonful of the dough on parchment paper (I used cheese cloth) and place them in a preheated steamer. Steam for about 10 minutes.
*makes 8-10 cakes
The consensus? We all loved them! They weren't especially pretty to look at (but they're supposed to be devilish, right?) but they were mildly sweet and chewy and yummy. And so easy to make. A keeper all around.
Afterwards we went out onto the back deck and threw our beans over the rails yelling, "Demons out, good fortune in!"
I Can't imagine what the neighbors must think...