Put shredded taro root and carrot in a large bowl. Mix and use your palms to squeezes out all the liquid. Add tofu, onion, and garlic with taro and carrot. Mix well. Season with sugar, soy sauce and black pepper. Set aside. Mix water with cornstarch in a small bowl. Set aside. Gently separate the spring roll shells. Lay one sheet flat on a cutting board or plate, fill 1/3 of the shell with the mixed vegetables. Wrap the vegetable filling in spring roll shell, roll it tight and seal the end with cornstarch water. Heat 6 cups of cooking oil on high temperature. When hot, lower the temperature to medium. Turn spring rolls frequently and deep fry till golden brown. Serve hot with sweet soy sauce.