Cut sweet potatoes and taro into cubes and steam them in water; peel them, sprinkle with sugar and tapioca flour while hot, and mash them; knead them to form smooth doughs; (remember to add water during the process) and knead into long strips and cut into small pieces to make Taro balls; put in boiling water, cook until floating, turn to low heat and cook for 3 minutes; remove and put in ice water for later use. Lay out. Add taro balls and instant bird's nest; drizzle with condensed milk, sprinkle with chopped nuts, and enjoy.