Soak the Chinese mushrooms in hot water until soft, about 5 minutes. Then finely chop.
Heat the olive oil in a large nonstick pan and cook the onion for a few minutes. Add the mushrooms and cook for another 2 minutes. Add the ground chicken and cook for 4 to 6 minutes, mixing the meat with the other ingredients as it cooks, so it breaks up into little pieces. Add the mirin or wine followed by the sesame oil, sesame seeds, oyster sauce, soy sauce, water chestnuts and garlic. Cook for a few minutes and let the mixture caramelize. Add the spring onions and remove from the heat. Spread a bit of plum sauce on the inside of each radicchio leaf. Then top with a spoonful of the chicken mixture. A viewer or guest of the show, who may not be a professional cook, provided this recipe. The Food Network Kitchens chefs have not tested this recipe and therefore, we cannot make representation as to the results.