This is a variation of dduk (tteok) or Korean rice cake using glutinous rice flour (chapssal) and red beans. Another form of chapssal dduk resembles the Japanese mochi -- a round ball with a sweet red bean filling (for that recipe, go here). My recipe below is for chapssal dduk that is more like a cake.
2 cups red beans, also called azuki beans, (pat 팥)
1 lb sweet rice flour
1 cup water
1 cup sugar
salt 2 tsp
Cover beans with water in a large pot. Bring to a boil and cook until it becomes very tender ... this should take 20-30 minutes. Drain if there is any excess water. Note: soaking beans ahead of time shortens cooking time.
Mix the sweet rice flour, water, sugar and salt, stirring well. Place in a plastic container with plastic wrap and let sit for 1/2 hour.
Preheat oven to 350F.
Get a rectangular pan ready (I used a 13x9x2 sized pan) ready -- lightly oil the sides and bottom and dust it with flour.
Spread a layer of cooked bean about 1" thick. Then spread a layer of the rice batter using 1/2 the amount. Spread another layer of cooked bean, then spread the remaining rice batter in a new layer.
Seal with aluminum foil and bake at 350F for 1 hour. Turn the heat off, and leave it in the oven for about another hour. Remove from heat and let sit at room temperature for about 10 minutes. Cut into thinnish rectangles and serve.