Cut the shiitake mushrooms into quarters with a pair of kitchen scissors and soak them in a bowl with plenty of boiling water. Soak for 30 minutes
Add the black fungus into a bowl with plenty of boiling water. Soak for 30 minutes.
Prep the vegetables. Remember to dry the vegetables with kitchen towels whenever possible.
Finely chop the sweet potato and put it into a bowl. Add a 1 tbsp of water, cover the bowl with cling wrap and put it in the microwave for 4.5 minutes on high. With a fork, mash the sweet potato and leave aside uncovered.
Cut the tofu into smaller chunks and mash it with your fingers in a large bowl. Using paper towels, squash the tofu against the bowl to remove moisture. Leave aside
Take out the shiitake mushrooms and squeeze out the liquid. Pat dry and chop. Repeat with the black fungus.
Heat a non stick frying pan on medium and a tbsp of oil. Sweat the onions until starting to turn golden
Add the mashed tofu, shiitake mushrooms and black fungus and fry for a few minutes. Add 2 tbsp of soy sauce, salt and pepper. Continue stirring and cook off the moisture for at least 5 minutes. Set aside and allow to cool.
In a bowl, add the cabbage, carrot, sweet potato, rinsed bean thread and sugar. Mix well. Then add the cooled tofu mixture and combine well with your hands. (Make sure to fully incorporate the mashed sweet potato.)
Allow the to sit for 15 minutes so that that bean thread can soak up the liquid in the mixture.
Add the cornstarch and 2 tbsp of water into a small bowl. Microwave for 20 seconds or until it goes gooey.