1/2 cup unsalted butter
1 1/4 cups white sugar
1 teaspoon vanilla extract
3 cups flour
1 teaspoon baking powder
3 cups milk
1 (18.75 ounce) can sweetened red bean paste
Preheat oven to 350 degrees F (175 degrees C).
Grease a 9×13 inch baking pan.
In a large bowl, mix together the butter, sugar, eggs, vanilla and milk.
Stir in the rice flour and baking powder.
Pour the batter into the prepared pan.
Drop red bean paste by scant teaspoonfuls onto the top of the cake.
Bake for 1 hour in the preheated oven, or until cake springs back when lightly touched.
Flip it out of the cake pan.
Let cool and sprinkle with powdered sugar.