Cha Manju (Tea Sweet Buns)

Make Koshian: 1. Wash beans and simmer with 4 cups water for 40-50 minutes until soft. 2. Drain and mash beans. Push through mesh strainer under water to remove skins. 3. Squeeze out water through cloth. Knead in water to remove bitterness, then squeeze dry. 4. Cook paste with equal amount of sugar over low heat, add salt. Make Manju: 1. Mix brown sugar with 1 tablespoon water and white sugar. Heat until melted, let cool. 2. Mix baking powder with 2/3 teaspoon water, add to sugar mixture. 3. Sift flour and add to liquid. Knead into log, divide into 12 pieces. 4. Make 12 balls of koshian. Wrap each in dough, sealing edges. 5. Place each on 1-inch square of wax paper. 6. Steam over boiling water for 12-15 minutes.