In another pot of boiling water add red beans and cook until they open. Allow cooling, then put in blender. (add 0.5 c water) Blend into a fine paste.
(1) 紅豆洗淨，以清水浸泡四﹘六小時後，把水倒掉，另煮一鍋清水，大滾後倒入紅豆煮至豆皮裂開，待稍涼置入果汁機中（加水半杯）打成細糊，裝進乾淨的麵粉袋中紮緊壓去水分，即是純豆沙。