In a small bowl, whisk together the brown sugar, shoyu, and mirin and set aside. Place the dried shiitakes in a bowl and cover with warm water to soften. Place the noodles in a bowl and cover with warm water to soften.
In a large wok or Dutch oven, heat the sesame oil over medium-high heat. Add the chicken, increase the heat to high, and saute until the meat is mostly cooked, 3 to 4 minutes.
Add the ginger and garlic and saute until fragrant. Add the carrots, onion, baby corn, bamboo shoots, shoyu mixture, and Chicken Broth.
Reserving the soaking liquid, drain the mushrooms, cut off and discard any stems, and slice the caps. Add them and the soaking liquid to the pan. Bring all of this to a boil, then reduce the heat and simmer for 10 minutes.
Drain the cellophane noodles (they should be softened at this point) and cut into 3-inch lengths. Add them to the pan along with baby bok choy, aburage and tofu. Simmer until bok choy are blanched but firm about 2 to 3 minutes. Finish by folding in watercress and scallions.
Serve with cooked rice if desired.
Serves 4-6